CN113196853B - Side chain resource allocation - Google Patents

Abstract

A method of increasing resource availability for sidelink communications in a wireless cellular communication system. In addition to reserving resources in the resource pool, resources may be allocated for sidelink communications using signaling from the base station to the UE. The SCI message may be used to share the indication to other UEs. The resource can be activated indefinitely or within a certain period of validity.

Description

Side chain resource allocation

Technical Field

The present application relates to allocation of transmission resources in a cellular communication network, in particular for sidelink communications.

Background

Wireless communication systems, such as third generation (3G) mobile telephone standards and technologies are well known. The 3G standards and techniques were developed by the third generation partnership project organization (3 GPP). Third generation wireless communications were generally developed to support macrocell mobile telephone communications. Communication systems and networks have evolved towards broadband and mobile systems.

In a cellular wireless communication system, user Equipment (UE) is connected to a Radio Access Network (RAN) over a wireless link. The RAN includes a set of base stations. The set of base stations provides radio links to UEs located within the cell covered by the base station. The set of base stations provides an interface to a Core Network (CN) that provides overall network control. It will be appreciated that the RAN and CN each perform functions related to the overall network. For convenience, the term cellular network will be used to refer to the merged RAN and CN, and it will be understood that this term is used to refer to the respective systems that perform the functions described herein.

The third generation partnership project organization developed a so-called Long Term Evolution (LTE) system, evolved universal mobile telecommunications system terrestrial radio access network (E-UTRAN), for mobile access networks, in which one or more macrocells are supported by base stations called enodebs or enbs (evolved nodebs). Recently, LTE is being further developed towards so-called 5G or NR (new radio) systems, where one or more cells are supported by a base station called a gNB. NR is proposed to use an Orthogonal Frequency Division Multiplexing (OFDM) physical transmission format.

In conventional cellular communication networks, all signaling is between each mobile device and the base station, rather than directly between the mobile devices, even though the mobile devices are within wireless communication range of each other. This may result in inefficient utilization of radio transmission resources and may increase utilization of base station resources. Sidelink communications allow mobile devices to communicate directly rather than through base stations, potentially increasing utilization of radio and base station resources. Side-chain communication is considered to be particularly interesting for machine-to-machine communication, in particular vehicle-to-vehicle (V2V) and vehicle-to-outside (V2X) communication.

The following disclosure relates to various improvements in cellular wireless communication systems, and in particular to sidelink communications in such systems.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

The present invention provides a method of activating additional resources for sidelink communication in a wireless cellular communication system, the method comprising the steps of: an indication of additional resources available for sidelink transmissions is transmitted from the base station to the UE. The indication may be transmitted to a first UE, which then transmits an indication of resources to a second UE via an SCI message. Alternatively, the indication may be transmitted directly from the base station to all relevant UEs. The resources may be represented by a bitmap, each bit being associated with a time slot, or by referring to a preset complementary resource pool.

A validity period may be defined during which resources are still available without further indication. After this expiration period, the resource is automatically no longer available. Any suitable signalling may be utilised, for example DCI, SCI or RRC, depending on the nature of the update required, the priority of the overhead and the elements involved in any update.

The non-transitory computer readable medium may include at least one of the following features: hard disk, CD-ROM, optical storage devices, magnetic storage devices, read-only memory, programmable read-only memory, erasable programmable read-only memory, EPROM, electrically erasable programmable read-only memory, and Flash memory.

Drawings

Further details, aspects and embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. To facilitate understanding, similar reference numerals have been included in the various figures.

FIG. 1 illustrates a schematic diagram of selected components of a cellular communication system;

FIG. 2 illustrates an example of two resource pools;

FIG. 3 illustrates an example of additional resource allocation;

FIG. 4 illustrates an example of utilizing additional resources;

FIG. 5 illustrates a flow chart for allocating additional resources;

FIG. 6 illustrates an example of a supplemental resource pool; and

FIG. 7 illustrates a flow diagram for activating a supplemental resource pool.

Detailed Description

Those skilled in the art will recognize and appreciate that the specifics of the described examples are merely illustrative of some embodiments and that the teachings herein may be applied in a variety of alternative settings.

Fig. 1 shows a schematic diagram of a cellular network composed of three base stations (e.g., enbs or gnbs, depending on the particular cellular standard and terminology). Typically, each base station is deployed by a cellular network operator to provide geographic coverage for UEs in the area. The base stations form a Radio Access Network (RAN). Each base station provides radio coverage for UEs of its area or cell. The base stations are connected to each other via an X2 interface and to the core network via an S1 interface. It will be appreciated that only the essential details are shown in order to illustrate the main features of the cellular network. In the proposed NR protocol, the Uu interface is between the base station and the UE. A PC5 interface is provided between the UEs for Sidelink (SL) communication. The interface and component names mentioned in fig. 1 are for example only, and different systems, operating according to the same principles, may use different nomenclature.

Each base station includes hardware and software that performs the functions of the RAN, the functions of the RNA include communication with the core network and other base stations, the carrying of control and data signals between the core network and the UEs, and the maintenance of wireless communication with the UEs associated with each base station. The core network includes hardware and software that implement network functions, such as overall network management and control, and routing of calls and data.

The side-chain transmission utilizes TDD (half duplex) on a dedicated carrier, or a shared carrier with the conventional Uu transmission between the base station and the UE. A resource pool of transmission resources is used to manage resources and allocation and to manage interference between transmissions that may be simultaneous. A resource pool is a set of time-frequency resources from which resources may be selected for transmission. The UE may be configured with multiple transmit and receive resource pools.

In LTE-V2X (Rel 14), the resource pool may be configured by cell-specific signaling (SIB 21) or RRC signaling. The basic Information Element (IE) is SL-CommResourcePoolV2X-r14 as defined in TS36.331 (e.g. V14.5.1), the parameters of which are shown in Table 1 below

Table 1: time-frequency parameters in resource pool configuration SL-CommResourcepool V2X-r14

TS36.331 also defines (section 14.1.5) how resource pools are defined based on these parameters. All subframes starting from System Frame Number (SFN) 0 or Direct Frame Number (DFN) 0 (depending on whether the UE is in coverage or out of coverage), respectively, may be used for SL transmission, except for the following subframes:

1. the subframes for SLSS resources are configured.

2. Downlink subframes and special subframes if the sidechain transmission occurs in a TDD cell.

3. Some special reserved subframes.

The remaining subframes are arranged in order of increasing Subframe index and the configured bitmap sl-Subframe-r14 is applied. Where 1 indicates that the subframe is included in the pool and 0 indicates not included. In the frequency domain, the PRBs contained in the resource pool are given by nPRB = nsubCHRBstart + mnubchsize + j, where m =0,1,.., nsubCH-1, nsubCHRBstart, subbcize, and NsubCH are specified by the high layer parameters startRB-Subchannel-r14, sizesubcchannel-r 14, and numbicchannel-r 14, respectively.

As described above, DL and some special reserved subframes cannot be used for the sidelink resource pool to avoid the possibility of interference to system information. That is, only UL subframes are available for the SL resource pool.

In previous standards (LTE in particular), subframes were designated as UL or DL, with various configurations, as specified in table 4.2-2 of TS 36.331. Up to 6 subframes in a frame may be defined as UL, providing the largest resources for sidelink communications.

In LTE-V2X, the selection of resources for a particular transmission may be made according to two allocation modes. In mode 3, the base station allocates a sidelink resource, which the UE cannot modify. In mode 4, each UE autonomously selects resources for each transmission from its allocated resource pool.

In mode 3, the UE transmits a Scheduling Request (SR) or a Buffer Status Report (BSR) to the relevant base station, and the base station responds with DCI (format 5 A0) on the PDCCH to grant sidechain transmission. The UE then transmits PDSCH on the first available subframe 4+ m ms after receiving DCI, with an offset m ∈ {0,1,2,3} only hinted in DCI for TDD operation. The first available subframe is selected from all resource pools configured for the UE, so if the base station intends to transmit on one particular resource pool, the DCI must have the appropriate time. The first available subframe may be part of more than one resource pool, thus leading to ambiguity that can be resolved by the frequency resource allocation.

The NR criteria include some differences that may render existing side-chain resource allocation procedures unsuitable. For example:

different numbers: time slots are elementary time intervals, the length of which depends on the spacing of the subcarriers

Flexible TDD:

a. there is no pre-configured set of UL-DL configurations, but the number of UL and DL slots and the number of symbols can be flexibly configured.

b. In addition to UL and DL slots/symbols, there are flexible (F) slots/symbols, which can be used for either UL or DL.

c. Only the cell-wide UL-DL configuration is absent: the F slots/symbols in the cell-wide configuration may be covered by the UE-specific configuration. It may also be covered with dynamic signaling through DCI 2.0.

New service: the resource pool is likely to support broadcast, multicast and unicast transmissions, all with different throughput, reliability and delay requirements.

In NR, a cell-specific (normal) TDD UL-DL configuration (TDD-UL-DL-ConfigCommon) is obtained in IE servingcellconfigcommon SIB of the SIB1 signal, and includes a reference subcarrier spacing and at most two UL-DL modes. For purposes of explanation, the example of the 15kHz subcarrier spacing pattern shown in Table 2 below will be used:

table 2: example of configuration of TDD-UL-DL-mode

The configuration defined in table 2 is shown in fig. 2. Fig. 2 shows two repeated 10-slot (10 ms) UL/DL patterns and resource pools of length 20 slots (20 ms). The figure shows 6 frequency subchannels.

Two resource pools-RP 0 and RP1 are shown in FIG. 2. RP0 uses only UL slots, while RP1 uses both uplink and flexible slots. RP0 has resources available every 10ms, but since RP1 uses flexible slots, the resource pool has a higher frequency of resource availability, potentially reducing latency. However, the UE monitors PSCCH transmissions at every slot of its configured resource pool, so RP1 needs to monitor more frequently than RP0, resulting in potentially greater power consumption.

There are two resource allocation patterns available — pattern 1 and pattern 2. In mode 1, the base station configures a sidelink resource, and in mode, the UE autonomously selects from pre-configured resources. In mode 2, the UE may not be allowed to transmit on flexible time slots because the UE may unknowingly cause interference to neighboring cells that may use these time slots for DL transmissions.

Listed below are resource allocation methods, which attempt to address the above-mentioned technical shortcomings.

As shown in fig. 2, some of the time slots are "partial time slots" and may contain DL & F or UL & F regions. That is, a portion of the time slot may be used for DL and a portion may be flexible (similarly, a portion may be used for UL and a portion is flexible). Such UL/F fractional time slots may also be included in the sidelink resource pool.

To reduce monitoring scenarios, the UE may be configured to monitor the PSCCH only on full/partial UL slots, even if the resource pool comprises flexible slots. For example, in fig. 2, a UE configured with RP1 may monitor the PSCCH only in slot 8, slot 9, slot 17, and slot 18. Furthermore, control information may only be transmitted in the complete DL slot, and thus no monitoring may be needed in slot 17, leaving only slot 8, slot 9 and slot 18 to be monitored.

The configuration of the monitored slots may be by any suitable signaling mechanism, such as RRC or DCI/SCI.

Table 3 below shows an example of a signaling scheme.

Table 3: example PSCCH monitoring configuration possible per RP per UE

Reducing the number of time slots to monitor the PSCCH may reduce power consumption without reducing the number of time slots available for SL transmissions.

The available flexible time slots within the resource pool may be dynamically configured, e.g., using DCI/SCI signaling. In one example, availability may be represented using a bitmap. The length of the bitmap is equal to the number of all or part of the time slots containing flexible resources within one UL/DL mode period. When the bit is set to 1, the corresponding slot is available for SL transmission, and when the bit is set to 0, the corresponding slot is not available. When one time slot is indicated as available, the frequency resources are the same as the resource pool configured for the UE.

FIG. 3 shows the same RP0 and RP1 as FIG. 3, but with two additional sets of resources (Add RP0, add RP 1) that may be added to each resource pool through dynamic signaling. In this example, the length of the bitmap is 6, corresponding to flexible time slots 2-7 (and 12-17).

The resource pool configured for the UE may indicate that a certain time slot is available, but the bitmap may indicate that the time slot is not available, and this conflict must be resolved according to defined rules. For example as occurs in slot 13 in fig. 4. There are two principle options:

·resource pool configuration has priority over bitmap: the bitmap cannot cover the resource pool configuration. Accordingly, in fig. 4, slot 13 would be available for SL transmission.

·Bitmap versus resource pool configuration priority: the bitmap covers the resource pool configuration, so in fig. 4, slot 13 cannot be used for SL transmission.

The second option, which may be most attractive since the purpose of dynamic signaling is to achieve a more flexible reconfiguration, allows the network to modify the previous semi-static configuration. The bitmap is only one example of a possible signaling mechanism and any suitable signaling method may be utilized in accordance with these principles.

As described above, in mode 1, the base station selects the transmission resources that the UE uses for SL transmission and indicates these resources to the UE in a DCI message. To decode efficiently, the size of the DCI message must be known prior to transmission, and therefore, the indication of the additional resources available for SL transmission may be included in the DCI scheduling SL transmission, or in a separate DCI not scheduling SL transmission (i.e., the DCI only modifies SL resource pool allocation).

The availability of processes with additional resources may be activated or deactivated using higher layer or dedicated signaling. This activation or deactivation makes the UE aware of the size and format of the DCI message it is seeking to decode (with or without possible additional resource indications). Once the UE knows whether these procedures are activated, the UE knows which sizes of DCI to search for.

Once the UE (TX-UE) receives the DCI, the UE must forward the information to the UE (RX-UE) that receives the transmission, so that the extra resources can be utilized. This may be achieved by the methods shown in fig. 4 and 5. In another case, the base station may forward the resource information (as indicated by the bitmap) directly to the RX-UE.

In step 500, the TX-UE receives the DCI message 400. The DCI includes scheduling information for SL transmission to the RX-UE, as well as an indication of additional resources available for SL transmission (e.g., in the form of a bitmap as discussed above). The TX-UE decodes the DCI and determines the first slot in which the SCI can be transmitted in step 501. In this case, the first slot is slot 5 (N +4= 5), but there is no transmission resource available in slot 5.

At this stage, only the resources in the resource pool are available, since the TX-UE has not forwarded an indication of any additional resources allocated by the base station in the DCI. Thus, the first available transmission resource is slot 8 at RP1. Thus, in step 502, the TX-UE transmits the relevant SCI at slot 8, including the additional resource indication received from the base station.

In step 503, the rx-UE decodes the SCI transmitted in slot 8, and the associated PSSCH (if in the same slot). In step 504, the rx-UE identifies the additional resources indicated as available and allocates them as part of the RP1 resource, so that the resources in time slot 12, time slot 14 and time slot 15 become available as well. The additional resources may be associated with the resource pool using any suitable technique. For example, the UE may implicitly recognize from the time constraints of SCI (N +4from DCI) transmissions that these resources are related to RP1. Since the base station knows all the allocated resource pools, the base station can lock the required resource pools by the time of the message. In another example, explicit signaling may be used, e.g., in DCI, to indicate a resource pool, e.g., using RP-IDs.

In step 505, additional DCI messages may be received in slot 5, slot 6, slot 7, and slot 8, SL transmissions may be scheduled in slot 12, slot 13, slot 14, and slot 15, and newly allocated additional resources may be used for transmissions. An indication of additional resources, e.g., using a bitmap, thereby making additional transmission resources available for SL transmission.

An indication of additional resources may be included in each SCI and assumed to remain valid until changed by further DCI/SCI messages. However, this may add a significant amount of overhead to SCI messages. A "validity period" may be defined in relation to the additional resources and their indications, such that after the validity period it is assumed that the additional resources are no longer available, only the resource pool resources are available.

The validity period may be defined to start as soon as the SCI is received by the RX-UE, or, if HARQ feedback is activated, as soon as the PSFCH is received by the TX-UE after the first transmission of an SCI indicating additional resources. The latter may ensure that the RX-UE successfully decodes the SCI, knowing the extra resource situation.

Similarly, the time limit may be defined in a series of ways, such as:

1. the number of UL-DL mode periods after the start of the UL-DL mode period at the beginning of the validity period. For example, in FIG. 4, for option 1, the validity period begins at slot 8 (SCI received), so the first cycle of the validity period is slots 0-9 and the second cycle is slots 10-19.

2. Defined as a time, e.g., ms, independent of the UL-DL period. For example, assume that an expiration period starting at option 1,5ms would start at slot 8 and expire after slot 12, meaning that only slot 12 is added to the resource pool.

3. The validity period may be defined as a number of time slots, the time of which will depend on the number, since the time of a time slot depends on the spacing of the subcarriers.

4. Defined in terms of the periodicity of the resource pool. The parameters, such as SL-Subframe-r14, define the resource period, e.g., 100 bits/SL slot. Thus, the original resource pool is not modified, but the indicated extra slots are available for SL transmission. For example, if the validity period is 2 resource pool periods, then additional SL resources are available in the current resource pool period and the next resource pool period.

The use of the validity period may enable the extra resource indication to be transmitted only in the first DCI and not repeated within the validity period, thereby reducing signaling overhead.

Just like DCI, the UE needs to know the size of the SCI message the UE is to decode. The additional resource indication may be included in an existing format or a new format may be defined. Further, in the case of utilizing a 2-stage SCI program, resources may be indicated in the second-stage SCI. In another example, the first phase of the SCI program may be utilized. Using the first stage may be advantageous because the SCI message may be decoded by all UEs, thereby making all UEs aware of the resources used. Similar to DCI, overhead may be reduced by utilizing the validity period discussed above, such that only the first SCI message needs to include an indication of additional resources within the validity period. Furthermore, the RX-UE does not need to attempt to decode the SCI format including the indication within the validity period.

To manage the signaling overhead associated with the additional resources for side link communications, one or more supplemental resource pools (CRPs) may be defined for use with the standard resource pool to expand the available resources. CRPs can be activated in a semi-static or dynamic manner, with only a small overhead due to the limited number of CRPs defined. Since the frequency domain resources in the resource pool are fixed, one or more CRPs may be associated with one resource pool.

Fig. 6 illustrates an example of two CRP in relation to the resource pools discussed in the above example, and fig. 7 illustrates a flow chart of a method of semi-static configuration using CRP.

At step 600, the relevant UE is configured (e.g., through RRC signaling) with RP0 and RP1 resource pools, and supplemental resource pools CRP0 and CRP1. In step 601, the ue monitors SCI over PSCCH on the configured resource pool resources (but not CRP resources). In step 602, the base station sends a DCI message to the TX-UE to schedule a SL transmission, including an indication to activate both CRPs. In another example, only one CRP to be transmitted may be activated.

In step 603, the tx-UE decodes the DCI information and marks the relevant CRP as active. In step 604, the tx-UE sends a SCI message to the associated RX-UE including an indication to activate CRP as indicated by the DCI. Once activated, the RX-UE monitors the SCI, CRP, and resource pool resources, beginning at step 605. CRP remains activated until indicated otherwise.

At step 606, a similar DCI/SCI disabling procedure may be utilized when CRPs are no longer needed.

Since there are only two CRPs in this example and both CRPs remain active indefinitely, the signaling overhead is reduced compared to indicating each slot separately. For example, in this example, only 2 bits are needed to represent two CRPs. Likewise, if only one CRP is defined, only one bit is required. The activation/deactivation signal may utilize any suitable signaling. For example, the state of a CRP may also be switched if a bit related to the CRP is switched, or set inactive if a bit is 0 and set active if the bit is 1.

In a variation of the above example, the base station may send a signal, e.g., a DCI signal, to all relevant UEs to activate CRP instead of forwarding the indication through TX-UE and SCI.

Similar validity periods may apply for CRP, as described above with respect to additional resources. The validity period may be preconfigured by CRP, semi-statically indicated by RRC signaling, or dynamically indicated by DCI/SCI signaling. The first two options avoid SCI/DCI overhead. The validity period may be explicitly indicated in the DCI/SCI message. As described above, during the validity period, the SCI format without a validity period indication may be utilized to reduce overhead.

If the UE switches from mode 1 to mode 2 resource allocation, all CRPs may be disabled to avoid interference, but if activated by TX-UEs, mode 2 UEs may still receive on the resource pool and CRPs.

The association between a resource pool and a CRP may be implicit or explicit if the CRP uses the same frequency domain resources as the resource pool, i.e. an indication of the relevant resource pool is included in the configuration or activation signal (e.g. using the RP-ID).

Although not shown in detail, any device or apparatus forming part of a network may comprise at least a processor, a memory unit, and a communication interface, wherein the processor unit, memory unit, and communication interface are configured to perform the method of any aspect of the invention. Further options and choices are described below.

The signal processing functions of embodiments of the present invention, particularly the signal processing functions of the gNB and UE, may be implemented using computing systems or architectures known to those skilled in the relevant art. Such as a desktop, laptop or notebook computer, hand-held computing device (PDA, cell phone, palmtop, etc.), mainframe, server, client, or any other type of special or general purpose computing device that may be desirable or appropriate for a particular application or environment. The computing system may include one or more processors, which may be implemented using a general-purpose or special-purpose processing engine, such as a microprocessor, microcontroller or other control module.

The computing system may also include a main memory, such as a Random Access Memory (RAM) or other dynamic memory, for storing information and instructions to be executed by the processor. Such main memory may also be used for storing temporary variables or other intermediate information during execution of instructions to be executed by the processor. The computing system may also include a Read Only Memory (ROM) or other static storage device for storing static information and instructions for the processor.

The computing system may also include an information storage system comprising, for example, a media drive and a removable storage interface. The media drive includes a drive or other mechanism to support fixed or removable storage media, such as a hard disk drive, a floppy disk drive, a magnetic tape drive, an optical disk drive, a Compact Disk (CD) or Digital Video Drive (DVD) read or write drive (R or RW), or other removable or fixed media drive. The storage medium may include, for example, a hard disk, floppy disk, magnetic tape, optical disk, CD or DVD, or other fixed or removable medium that is read by and written to by a media drive. The storage media may include a computer-readable storage medium having stored therein particular computer software or data.

In another embodiment, an information storage system includes other similar components for allowing computer programs or other instructions or data to be loaded into the computing system. These components may include, for example, removable storage units and interfaces, such as a program cartridge and a program cartridge interface, removable memory (for example, a flash memory or other removable memory module) and a memory slot, and other removable storage units and interfaces that allow software and data to be transferred from the removable storage unit to the computing system.

The computing system may also include a communication interface. Such a communication interface may be used to allow software and data to be transferred between the computing system and external devices. Examples of communications interfaces include a modem, a network interface (such as an ethernet or other network interface card), a communications port (such as a Universal Serial Bus (USB) port), a PCMCIA slot and card, etc. Software and data transferred via the communications interface are in the form of signals which may be electronic, electromagnetic and optical or other signals capable of being received by the communications interface medium.

As used herein, the terms "computer program product," "computer-readable medium" and the like may generally refer to a tangible medium, such as a memory, a storage device, or a storage unit. These and other forms of computer-readable media may store one or more instructions for use by a processor comprising a computer system, to cause the processor to perform specified operations. Such instructions, generally referred to as 'computer program code' (which may be grouped in the form of computer programs or other groupings), when executed, enable the computing system to perform functions of embodiments of the present invention. Note that the code may directly cause the processor to perform specified operations, be compiled into such, and/or be combined with other software, hardware, and/or firmware elements (e.g., libraries for performing standard functions) to perform the operations.

The non-transitory computer readable medium includes at least one of the following features: hard disk, CD-ROM, optical storage devices, magnetic storage devices, read-only memory, programmable read-only memory, erasable programmable read-only memory, EPROM, electrically erasable programmable read-only memory, and flash memory. In one embodiment where the elements are implemented using software, the software may be stored in a computer-readable medium and loaded into the computing system using, for example, a removable storage drive. The control module (in this example, software instructions or executable computer program code), when executed by a processor in a computer system, causes the processor to perform the functions of the invention as described herein.

Furthermore, the concepts of the present invention may be applied to any circuit that performs signal processing functions within a network element. It is further contemplated that, for example, a semiconductor manufacturer may employ the concepts of the present invention in the design of a stand-alone device, such as a microcontroller of a Digital Signal Processor (DSP), or an Application Specific Integrated Circuit (ASIC), and/or any other subsystem element.

It will be appreciated that the above description for clarity has described embodiments of the invention with reference to a single processing logic. The inventive idea may, however, equally be implemented by means of a number of different functional units and processors, providing signal processing functions. Hence, references to specific functional units are only to be seen as references to suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

Aspects of the invention may be implemented in any suitable form including hardware, software, firmware or any combination of these. The invention may alternatively be implemented at least partly in the form of computer software running on one or more data processors and/or digital signal processors or configurable modular components, such as FPGA devices.

Thus, the elements and components of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way. Indeed the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the invention is limited only by the attached claims. In addition, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term "comprising" does not exclude the presence of other elements or steps.

Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor. Furthermore, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. Furthermore, the inclusion of a feature in one category of claims does not imply a limitation to this category but rather indicates that the feature is equally applicable to other claim categories, as appropriate.

Furthermore, the order of features in the claims does not imply any specific order in which the features must be performed and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. Rather, the steps may be performed in any suitable order. Furthermore, singular references do not exclude a plurality. Thus, references to "a", "an", "first", "second", etc., do not preclude a plurality.

Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the invention is limited only by the appended claims. In addition, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term "comprising" or "comprises" does not exclude the presence of other elements.

Claims (6)

1. A method of activating resources between UEs for sidelink communication in a wireless cellular communication system, the method comprising:

sending an indication from a base station of the cellular communication system to a TX-UE indicating resources available to the TX-UE for sidelink transmission, wherein the resources indicated as available are time slots defined as flexible by the cellular communication system, the resources being available within a preset validity period, at the end of which the resources are no longer available;

wherein the TX-UE transmits a further indication of at least some available resources to RX-UEs in an SCI message, the available resources being at a first stage of the SCI message such that the SCI message can be decoded by all of the RX-UEs; or, the base station transmitting a further indication of at least some of the available resources to the RX-UE in a DCI message;

wherein the indication comprises an indication of a resource pool comprising time slots defined as flexible by the cellular communication system, the resource pool being associated with a resource pool used by the base station to transmit an indication to the TX-UE.

2. The method of claim 1, wherein the indication comprises a bitmap indicating available resources, wherein each bit corresponds to a time slot.

3. The method of any of claims 1-2, wherein the indication is in a DCI message.

4. The method according to any of claims 1-2, wherein the indication is in an RRC message.

5. The method of claim 1, wherein the validity period is defined in relation to periodicity of UL/DL patterns, as a time interval, as a number of time slots, or in relation to resource pool periodicity.

6. The method according to claim 1, characterized in that it comprises:

the time slot is a UE receiving configuration message indicating a time slot subset in a resource pool of the UE, the UE being configured to monitor sidelink control transmissions in the designated time slot subset through the resource pool;

wherein the subset of timeslots is (1) all sidelink timeslots, (2) sidelink timeslots configured for full uplink only, (3) sidelink timeslots configured for full or partial uplink only, or (4) sidelink timeslots configured for partial uplink only.

Images