CN116034623A - Periodic reservation of side-link communications in cellular networks - Google Patents

Abstract

A method of evaluating existing reserved transmission resources during reservation of the transmission resources. The method considers whether the existing reservation is periodic or aperiodic and may also consider other features such as RSRP, number of collisions and relative periodicity. Transmission resources may be excluded from selection based on characteristics and whether the reservation is periodic or aperiodic, etc.

Description

Periodic reservation of side-link communications in cellular networks

Technical Field

The present disclosure relates to a periodic reservation resource in a cellular network, in particular a periodic reservation resource for side-link communication.

Background

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

In a cellular wireless communication system, user Equipment (UE) is connected to a Radio Access Network (RAN) through a wireless link. The RAN includes a set of base stations that provide radio links to UEs in a cell covered by the base stations, and also provides an interface to a Core Network (CN) for overall network control. Notably, the RAN and CN each perform a respective function related to the overall network. For convenience, the term cellular network is used to refer to a combination of RAN and CN, it being understood that the term is used to refer to the corresponding system for performing the disclosed functions.

The third generation partnership project has developed a so-called Long Term Evolution (LTE) system, i.e. an evolved universal mobile telecommunications system area radio access network (E-UTRAN) for mobile access networks, wherein one or more macro cells are supported by base stations called enodebs or enbs (evolved nodebs). Recently, LTE is further evolving towards 5G or New Radio (NR) systems, where one or more cells are supported by base stations called gnbs. NR recommends the use of Orthogonal Frequency Division Multiplexing (OFDM) physical transport formats.

The NR protocol is intended to provide the option of operating in the unlicensed radio frequency range (referred to as NR-U). While operating in the unlicensed radio frequency band, the gNB and UE must compete with other devices for physical medium/resource access while operating in the unlicensed radio frequency band. For example, wi-Fi (RTM), NR-U, and LAA may use the same physical resources.

The trend in wireless communication is to provide lower latency and higher reliability services. For example, NR is intended to support ultra-reliable and low-latency communications (URLLC), while large-scale machine type communications (mctc) is intended to provide low latency and high reliability for small data packets (typically 32 bytes in size), with user plane latencyThe delay is 1ms, the reliability is 99.99999%, and the packet loss rate of the physical layer is 10 ^-5 Or 10 ^-6 。

The mctc service aims to support a large number of devices over a long lifecycle through an energy efficient communication channel, where data transmission with each device is occasional and infrequent. For example, one unit may need to support thousands of devices.

The following disclosure relates to various improvements to cellular wireless communication systems.

Disclosure of Invention

This abstract presents the concepts of the disclosure in a simplified form as will be further described in the detailed description that follows. This abstract is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to determine the scope of the claimed subject matter.

The present disclosure provides various methods to facilitate selected periodic reservation of resources.

The present disclosure provides a method of selecting resources for side-link transmission in a cellular communication network, comprising the steps of evaluating existing reserved resources, identifying periodic reservations, and marking those reserved resources as unavailable for selection.

The present disclosure also provides a method of selecting resources for side-uplink transmissions in a cellular communication network, comprising the steps of evaluating existing reserved resources, identifying periodic reservations, and applying a different periodic reservation threshold than non-periodic reservations to evaluate whether related resources are available for selection. The threshold may be related to the SL-RSRP of the reservation message of the associated reservation. The threshold may depend on the priority of the reservation and may be configured to not affect the functionality of the conventional priority regime.

The present disclosure also provides a method of selecting resources for side-uplink transmissions in a cellular communication network, comprising the steps of evaluating existing reserved resources, identifying a periodic reservation, and comparing the period of the existing periodic reservation with the period of the current reservation. If the reservation has the same period, or if the period is multiple, the reservation of reserved resources is not allowed.

The present disclosure also provides a method of selecting transmission resources for a side-link transmission of a cellular communication network, the method being performed on a user equipment, UE, comprising the steps of: determining the existing periodic reserved transmission resources; and marking the reserved transmission resources as unavailable, the reservation cannot be selected by the UE.

The present disclosure also provides a method of selecting transmission resources for a side-link transmission of a cellular communication network, the method being performed on a user equipment, UE, comprising the steps of determining existing reserved transmission resources; classifying the existing reserved transmission resources as periodic reserved resources or non-periodic reserved resources; and marking the existing transmission resources of the reserved transmission resources as unavailable based on the comparison result of the characteristics of the transmission resources corresponding to the reserved transmission resources and a threshold value, wherein the threshold value depends on whether the corresponding reserved transmission resources are the periodic reserved resources or the aperiodic reserved resources.

Wherein, the threshold value corresponding to the reserved resources is higher than the threshold value corresponding to the non-reserved resources.

Wherein, the threshold value corresponding to the reserved resources is equal to the sum of the threshold value corresponding to the non-reserved resources and the offset value.

Wherein the offset value is preset.

Wherein the offset value depends on a priority difference between the existing reserved transmission resources and the new reserved transmission resources.

Wherein the threshold value is also dependent on the priority of the respective reservation.

Wherein the characteristic is adjusted according to whether the existing reserved transmission resources are periodic reserved transmission resources or non-periodic reserved transmission resources.

Wherein the characteristic comprises a SL-RSRP value of a message signal corresponding to the transmission resource.

Wherein the method further comprises the step of comparing the period of the new reservation with the period of the existing period reserved transmission resources and marking the transmission resources of the existing period having the same period as the new reservation as unavailable.

Wherein the method further comprises identifying a number of collisions between the existing reserved transmission resources and a new periodic reservation and marking transmission resources of the existing reserved transmission resources as unavailable when the number of collisions exceeds a threshold.

The present disclosure also provides a method of selecting transmission resources for side-link transmission in a cellular communication network, the method being performed on a UE, comprising the steps of determining reserved transmission resources of an existing period; determining a period of the reserved transmission resources of the existing period; and when the period of the new reservation is the same as or a multiple of the period, marking the reserved transmission resources as being unable to be selected by the UE as a new period reservation.

Drawings

Further details, aspects and embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings. The components in the figures are for ease of illustration and are not necessarily drawn to scale. For ease of understanding, like components are given like reference numerals throughout the various figures.

Fig. 1 shows a schematic diagram of selected elements of a cellular communication network.

Fig. 2 shows a method of resource reselection.

Fig. 3 to 7 show flowcharts of the resource selection method.

Detailed Description

Those skilled in the art will recognize and appreciate that the specific details of the examples described are merely illustrative of some embodiments, and that the teachings set forth herein are applicable in a variety of alternative settings.

Fig. 1 shows a schematic diagram of three base stations (e.g., enbs or gnbs, depending on the particular cellular standard and terminology) that make up a cellular network. Typically, each base station is deployed by one cellular network operator to provide geographic coverage for UEs in the area. The base stations form a Radio Area Network (RAN). Each base station provides wireless network coverage for UEs in its area or cell. The base stations are interconnected through an X2 interface and connected with a core network through an S1 interface. To illustrate key features of a cellular network, only basic details are shown here. For Side Link (SL) communication between UEs via a PC5 interface. The interface and component names associated with fig. 1 are for example only, and different systems operating on the same principles may use different nomenclature.

Each base station contains hardware and software that implements RAN functionality, including communications with the core network and other base stations, control and data signaling between the core network and UEs, and UEs associated with each base station remain in wireless communication. The core network includes hardware and software that implements network functions such as overall network management and control, and routing of calls and data.

In addition to uplink/downlink communications between the UE and the base station, the UE may also implement side-uplink communications that directly communicate with each other. Fig. 2 shows a base station 102 forming a RAN, as well as a UE 150 with a side-link transmitter (SL Tx UE) and a UE 152 with a side-link receiver (SL Rx UE) in the RAN. UEs 150 and 152 are depicted as having a transmitter and a receiver, respectively, but this is only for explaining the specific communication period, and their roles may be reversed as well. Base station 102 communicates wirelessly with SL Tx UE 150 and SL Rx UE 152 via respective connections 154. SL Tx UE 150 and SL Rx UE 152 are used to communicate wirelessly with each other via side links 156.

The side-uplink transmission is performed on a dedicated carrier or a shared carrier using TDD (half duplex) with a conventional Uu transmission between the base station and the UE. The resource pool of transmission resources is utilized to manage resources and allocations and to manage interference between potentially concurrent transmissions. The resource pool is a set of time-frequency resources from which transmission resources can be selected. The UE may configure multiple transmit and receive resource pools.

There are two modes of operation for resource allocation for side-link communications, depending on whether the UE is within the coverage of the cellular network. In mode 1, V2X communications are operating within the coverage of a base station (e.g., eNB or gNB). All scheduling and resource allocation can be done by the base station.

Mode 2 is applicable when the side-link service is operating outside the coverage of the cellular base station, at which point the UE needs to schedule itself. For fair utilization, UEs typically use transmission resource allocation based on sensing. Selecting resources includes two steps. In step 1 the UE will identify resources that are considered to be alternative, and in step 2 the specific resources are selected for transmission. Step 1 may start with a set of all resources in the selection window and then delete those resources that are not considered candidate resources (e.g., resources reserved by another UE with SL-RSRP above the threshold). The step of selecting the resources may be a random selection, may have constraints such as HARQ timing and delay between resources.

In mode 2, the UE selects transmission resources that are desired for transmission and transmits a side-uplink control information (Sidelink Control Information, SCI) message indicating these resources. The receiver of the SCI message (which may be a single UE in unicast, a group of UEs in multicast, or all accessible UEs in broadcast) can learn the transmission details that can be expected through the SCI.

In NR, the resource pool may be configured to allow periodic resources to be reserved or used for side-link communication. When the periodic resources are reserved, the SCI message includes an indication of the reservation period, which may be based on higher layer configurations that may be received in RRC signaling.

One particular problem that may occur with periodic resource reservation is that if two UEs select overlapping resources with the same period, a repetition collision may occur. Also, if the reserved periodic resources have a common multiple of the period where collisions occur (e.g., 10ms and 15ms will occur every 30ms (half or third of the number of occurrences), each collision may result in transmission errors or preemption, resulting in the UE re-selecting resources, requiring additional signaling and processing.

In the present disclosure, the term "periodic reserved resources" is used to refer to resource patterns (typically indicated in the first stage SCI) in the time and frequency domains that repeat in a given period (also typically in the first stage SCI). The term "period" is used to refer to a single occurrence of a resource pattern in a periodic resource. A single period corresponds to an initial transmission and a reserved associated retransmission.

The following disclosure is directed to techniques for improving periodic resource selection for side-link communications. In particular, the resource selection procedure is adapted to distinguish between periodic reserved resources and non-periodic (e.g., dynamically granted) reserved resources. When the resource pool is configured to allow periodic reservation, all first stage SCIs comprise a reservation period and are therefore essentially periodic reservation resources. However, if the SCI specifies a periodicity of 0ms, then the SCI will be considered as an aperiodic reserved resource.

The introduction of coordination between UEs aims to reduce interference between transmissions and reduce the chances of preemption and reselection, thereby improving overall system performance. In particular, the previous periodic reservation resources may be marked as not selectable by the subsequent periodic reservations, or may be distinguished from non-periodic reservation resources in determining whether they are available. Further differentiation may be made based on the similarity between the previous reservation and the new reservation period.

The methods discussed herein are applicable to both initial selection and reselection of resources.

As described above, in step 1 of the resource selection procedure, for signals whose SL-RSRP value is above the predetermined threshold, the reserved resources thereof are considered to be unavailable. This procedure may be modified so that all resources reserved for a period are considered to be unavailable no matter how large the SL-RSRP value of the signal is reserved. It is still effective to decide whether resources are not available in practice according to the threshold value, since the UE has to be able to receive and decode SCI, which means that the SL-RSRP value of the received signal is not too low.

Such behavior may be configured by the network, for example using higher layer (RRC) signaling. May be configured for a particular unit or may be configured based on a resource pool. Furthermore, the behavior may be enabled by reserving resources or selected priorities for all periods. For example, reserved resources of higher priority may not always be available, while reserved resources of lower priority may be available, depending on the SL-RSRP value of the reservation message signal. Also, previous reservations having a higher priority than the new reservation may not always be available. As previously described, the thresholds for activation and required may be configured using higher layer (RRC) signaling. In an example, reservations of a particular priority may be made available at all times or unavailable at all times by setting the respective threshold to positive infinity or negative infinity (or another extremum that cannot be achieved in the operating system). These values may be stored in a dedicated table of priority thresholds, as described below.

While it is easier to implement binary decisions on availability to provide good predictability, flexibility may be limited and spectrum utilization may be reduced. Finer approaches can be taken, such as using different criteria for the supply of the previously reserved resources for periods and for non-reserved resources. Fig. 3 shows an example in which different SL-RSRP thresholds may be applied for periodic resources and non-periodic reserved resources.

Step 1 of the resource selection procedure starts in step 300 and the received reservation is evaluated in step 301 to determine RSRP, priority and/or aperiodic/periodic type (and potentially other parameters). If it is determined that the reservation is periodic, the method continues with step 302 and reserves a first RSRP threshold of the resource configuration for the period. If it is determined that the reservation is aperiodic, the method continues with step 303 and a second RSRP threshold configured for aperiodic reserved resources. The SL-RSRP value of the reservation message signal is compared to an associated threshold value at step 304. If the SL-RSRP value exceeds the correlation threshold, the resources are set to be unavailable in step 305, and if the SL-RSRP is below the correlation threshold, the resources are set to be available in step 306. Typically, the threshold for periodic reserved resources is higher than the threshold for non-periodic reserved resources. That is, periodic reservation of resources may enhance protection against preemptions and collisions.

The threshold may also depend on other factors, such as the prioritization of reservations discussed above. The threshold may be configured by higher layer (RRC) signaling and may be defined at a resource pool, unit, or other appropriate granularity. By defining applicable thresholds, general behavior regarding priorities can be maintained. For example, periodic reserved resources should be avoided from being protected from reserved resources of higher priority later.

The method in fig. 3 relies on specific thresholds defined for reservation type and priority. This configuration data may be reduced using the method shown in fig. 4, where the offset value is applied when evaluating the period reservation.

In fig. 4, steps 300 and 301 are as described with respect to fig. 3. However, if the reserved resources are periodic, the UE sets an offset value to the RSRP threshold for adjustment in step 400. The offset value of the threshold may be a pre-configured fixed offset value, such as 2dB or 3dB as set by a standard threshold table. Alternatively, the offset value may be defined in terms of a priority difference between the two reservations (i.e., the detected reservation and the reservation for which the UE is identifying resources). For example, the offset value may be defined as x dB x (priority_tx-priority_rx) (where x may be 3). The offset value may also be set to an upper limit to avoid exceeding the threshold for lower priority transmissions, thereby affecting proper operation of the priority system. For example:

-Th_periodic(P_rx，P_tx)＝max(Th_aperiodic(P_rx，P_tx)-offset(P_rx，P_tx)，Th_aperiodic(P_rx-1，P_tx)))

steps 304-306 are then performed as described in fig. 3, but based on the correlation threshold.

In another approach of fig. 4, the measured SL-RSRP value may be adjusted as described for the threshold in fig. 4 and compared to an unadjusted threshold. It is clear that the direction of adjustment will be opposite to the direction of adjustment of the threshold value, but the principle is the same. The effect of both methods is that periodic reserved resources are less likely to be selected than when the UE selects non-periodic resources for a new transmission.

In a further example shown in fig. 5, the relative periodicity of the previous reservation and the new reservation may be considered. Steps 300 and 301 are as previously described, but at step 500 the periodicity of the previous period reservation is evaluated compared to the periodicity of the new reservation. If the periods are the same, the resource is marked as unavailable in step 501, but if the resource has a different period, the method continues to consider SL-RSRP according to the threshold in step 502. The thresholding process may be as disclosed herein with respect to any of the previous examples or using conventional methods. If the threshold fails, the resource is marked as unavailable, or if the threshold is passed, the resource is deemed available in step 503.

The method of fig. 5 avoids that resources in each cycle of the cycle reservation collide (because the cycles are the same), but may allow fewer cycle collisions (subject to threshold testing). In a modification to the method of fig. 5, if the periodicity of the existing reservation and the new reservation are multiples of each other (as this would result in a repetition conflict), then the resources may be deemed to be unavailable.

The periodic comparison may take into account the frequency of occurrence of collisions, as shown in fig. 6. For example, a reservation of a pair of periods 10ms and 15ms will occur every 30ms (i.e. every 3 and 2 periods, respectively). The comparison criteria may be based on a ratio of periods to conflicts. In step 600, the relevant metric is compared to a collision threshold, and if the threshold fails, the resource is marked as unavailable in step 601. If the threshold is passed, then the resource is deemed available at step 503.

If the conflict ratio of one or both reservations is above a (pre) configured threshold, the resource is marked as unavailable in step 601. The ratio may be defined in accordance with the parameters discussed previously, such as priority.

The threshold comparison in step 502 may be performed using any of the techniques previously discussed herein or using conventional techniques.

Fig. 7 shows another method of using collision assessment in step 2 of the resource selection procedure, which applies after step 1 is performed in a conventional manner to the selection of resources that the UE intends to reserve during step 2 of the resource selection procedure in step 700. In step 701, the UE determines whether the reservation is a periodic reservation, and if not, the selection is considered valid at step 702. If the reservation is periodic, the UE evaluates the collision with previously reserved resources in step 703. The evaluation may be based on any of the criteria discussed above and below.

If the number of collisions is small (step 704), e.g., below a threshold, the selection is deemed valid at step 702. The threshold may be defined on any suitable basis, e.g. per resource pool or per UE, and may depend on priority as described before.

If the number of collisions is not small (i.e. exceeds the threshold), the UE will evaluate (step 705) if conflicting reserved resources exceeding the threshold are allowed. If such reserved resources are not allowed, the UE will return to step 700 to select a different resource. However, reserved resources with a large number of collisions (e.g. exceeding the second threshold) may be allowed, as these collisions may trigger the UE's preemption of existing reservations and reselection of new periodic reservations. The reselection process is relatively inexpensive in terms of control overhead and the large number of collisions means that few resources will be idle. Thus, at step 706, the UE checks if the second threshold is exceeded and moves to step 702 or 700 accordingly. It is apparent that steps 704-706 may be condensed into a set of checks for the appropriate threshold. The effect of these steps is that, depending on the configuration, reservations below a first threshold and above a second threshold may be allowed to collide.

The threshold used at step 706 may be defined in accordance with any of the principles previously discussed.

Examples of the various measures and criteria are presented below to evaluate conflicts between reserved resources during. These measures and criteria may be used in any of the related methods described above. The purpose of these criteria is to evaluate the conflicts that will occur, as well as the potential costs due to triggering preemption and reselection.

The collision that will occur is a function of the resource overlap during each period of the periodic reservation and the relationship of the two reserved periods. Metrics that may be used to evaluate collisions include the number of conflicting resources that calculate the single collision that will occur, and if the entire previous cycle reservation is reselected, it also indicates an unused reservation expiration loss. The number of cycles containing at least one collision may be used to indicate the number of SCI reservations and reselection that the collision will trigger. As previously mentioned, any metric may be based on a ratio value instead of an absolute number of metrics and criteria used may be a function of calculating the number of conflicting resources for a single conflict (which may be helpful in assessing the loss of unused resources if a new period reservation is made) and/or the number of periods of reserved resources for a period containing at least one conflict (the number of reselection and SCI reservations required for calculation, giving an indication of control signal overhead). As mentioned above, the criterion may also be based on a fraction or ratio, rather than an absolute count.

The criteria may be evaluated over a defined period, which may be a configured number of periods, a future time (in milliseconds or logical slots), such as t_scal/c_remainder, and/or a number of periods (or minimum or maximum values thereof) remaining in the period reservation resource. The period may be defined by a standard and/or according to a configuration of the UE. The threshold may depend on the method and period used to calculate the conflict, so the configuration should be defined as a set to ensure predictable behavior.

In an example, the period of evaluation may be a minimum value of the configured time (t_scal) and a remaining time of the period reservation resource. The first time period reservation resource of the first UE may have a period of 20ms with 3 transmissions per period. There are 3 cycles (20 milliseconds) left in the reservation. The second UE makes a preemptive reservation consisting of 10ms periods, creating a collision in each period. This can be calculated as: 1 out of 3 (1/3) transmissions of each cycle of the first reservation collide, 3 out of the remaining first reservation cycles (100%) collide at least once, or 3 out of the second (preemption) cycles (50%) collide at least once. In this example, the threshold may be set to 25% of the remaining period in which at least one collision occurs, in which case period reselection will occur. More complex evaluations may be performed using multiple criteria, each of which may have a different threshold.

For UEs in different situations or configurations, different values may be defined for different measures/criteria, e.g. as described above, which may depend on the priority order of the reservations. The thresholds, criteria, and metrics may be configured using higher layer (RRC) signaling and configuration.

The configuration discussed above in relation to RRC configuration may also be dynamically configured or updated using an appropriate signaling procedure.

Although not shown in detail, any of the devices forming part of the network may comprise at least a processor, a storage unit and a communication interface, wherein the processor, the storage unit and the communication interface are configured to perform the methods of any aspect of the invention. Further options and selections are described below.

The signal processing functions of embodiments of the present invention, particularly the gNB and the UE, may be achieved using computer systems or architectures known to those skilled in the relevant art. The computer system may be a desktop, laptop or notebook computer, handheld computing device (PDA, cell phone, palmtop, etc.), server, client, or any other type of general purpose computing device that may be used as desired for a given application or environment. The computer 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 computer system may also include a main memory, such as a Random Access Memory (RAM) or other dynamic memory, for storing information and instructions that may be executed by the processor. The 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 computer system may also include a Read Only Memory (ROM) or other static storage device for storing static information and instructions for the processor.

The computer system may also include an information storage system, which may include a media drive and a removable storage interface. The media drive may include a drive or other mechanism to secure or support a removable storage medium, 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) (RTM) read or write drive (including a writeable or erasable drive), or other removable or fixed media drive. Storage media may include, for example, 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 medium may include a computer-readable storage medium having stored therein specific computer software or data.

In alternative embodiments, the information storage system may include other similar components for allowing computer programs or other instructions or data to be loaded into the computer system. Such components may include, for example, removable storage units and interfaces such as program cartridge and cartridge interfaces, removable memory (e.g., flash memory or other removable memory modules) and memory slots, and other removable storage units and interfaces that allow software and data to be transferred from the removable storage units to the computer system.

The computer system may also include a communication interface. Such a communication interface may be used to allow software and data to be transferred between a computer system and an external device. Examples of communication interfaces may include modems, network interfaces (e.g., ethernet or other NIC cards), communication ports (e.g., universal Serial Bus (USB) ports), PCMCIA slots and cards, 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.

In this document, the terms "computer program product," "computer-readable medium," and the like may be used to generally refer to tangible media, such as memory, memory devices, or storage units. These and other forms of computer-readable media may store one or more instructions for use by a processor, including a computer system, to cause the processor to perform specified operations. Such instructions are often referred to as "computer program code" (which may be grouped in the form of computer programs or other groupings). When executed, the computer system is capable of performing the functions of embodiments of the present invention. Note that the code may directly cause the processor to perform the specified operations, be compiled to do so, and/or be combined with other software, hardware, and/or firmware elements (e.g., libraries for performing standard functions) to do so.

The non-transitory computer readable medium may include at least one of: hard disks, CD-ROMs, 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 embodiments where the components are implemented using software, the software may be stored in a computer readable medium and loaded into a computer 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 inventive concept may be applied to any circuit for performing signal processing functions within a network component. It is further contemplated that, for example, a semiconductor manufacturer may employ the inventive concepts 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.

For clarity, the above description describes embodiments of the invention with reference to a single processing logic. However, the inventive concept may equally be implemented by a number of different functional units and processors to provide signal processing functionality. Thus, 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 be implemented at least in part as computer software running on one or more data processors and/or digital signal processors or configurable module components such as FPGA devices.

Thus, the components and assemblies of embodiments of the invention can 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 appended claims. Furthermore, although features appear to be described in connection with particular embodiments, those skilled in the art will recognize that various features of the described embodiments can 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 be advantageously 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 claim category 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 worked 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," "the first," "the second," etc. do not exclude 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. Furthermore, although features appear to be described in connection with particular embodiments, those skilled in the art will recognize that various features of the described embodiments can be combined in accordance with the invention. In the claims, the term "comprising" or "comprises" does not exclude the presence of other elements.

Claims (12)

1. A method of selecting transmission resources for a side-link transmission of a cellular communication network, the method being performed on a user equipment, UE, comprising the steps of:

determining the existing periodic transmission resource reservation; and

the transmission resource reservation is marked as unavailable and a reservation cannot be selected by the UE.

2. A method of selecting transmission resources for a side-link transmission of a cellular communication network, the method being performed on a user equipment, UE, comprising the steps of:

determining the existing transmission resource reservation;

classifying the existing transmission resource reservation as a periodic resource reservation or an aperiodic resource reservation;

based on a comparison of the characteristics of the transmission resources corresponding to the transmission resource reservation with a threshold, marking the transmission resources of the existing transmission resource reservation as unavailable, wherein the threshold depends on whether the corresponding transmission resource reservation is the periodic resource reservation or the aperiodic resource reservation.

3. The method of claim 2, wherein the threshold corresponding to the periodic resource reservation is higher than the threshold corresponding to the non-periodic resource reservation.

4. A method according to claim 2 or 3, characterized in that the threshold value corresponding to the periodic resource reservation is equal to the sum of the threshold value corresponding to the non-periodic resource reservation and an offset value.

5. The method of claim 4, wherein the offset value is preset.

6. The method according to claim 5, characterized in that the offset value depends on a priority difference between an existing transmission resource reservation and a new transmission resource reservation.

7. A method according to any of claims 2-7, characterized in that the threshold value also depends on the priority of the respective reservation.

8. The method according to claim 2, characterized in that the characteristic is adjusted depending on whether an existing transmission resource reservation is a periodic transmission resource reservation or an aperiodic transmission resource reservation.

9. A method according to any one of claims 2 to 8, characterized in that the characteristic comprises a SL-RSRP value of a message signal corresponding to a transmission resource.

10. The method according to any of claims 2 to 9, further comprising the step of comparing the period of the new reservation with the period of the existing periodic transmission resource reservation and marking the transmission resources of the existing period having the same period as the new reservation as unavailable.

11. The method according to any of claims 2 to 10, further comprising identifying a number of collisions between the existing transmission resource reservation and a new periodic reservation and marking transmission resources of the existing transmission resource reservation as unavailable when the number of collisions exceeds a threshold.

12. A method of selecting transmission resources for side-link transmissions in a cellular communication network, the method being performed on a UE, comprising the steps of:

determining transmission resource reservation of the existing period;

determining a period of the transmission resource reservation of an existing period; and

and when the period of the new reservation is the same as or is a multiple of the period, marking the transmission resource reservation as a reservation which cannot be selected by the UE as the new period.

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