WO2024114911A1

WO2024114911A1 - Adaptive buffer bands for direct terminal-device-to-terminal-device communication

Info

Publication number: WO2024114911A1
Application number: PCT/EP2022/084039
Authority: WO
Inventors: Nuno Manuel KIILERICH PRATAS; Oana-Elena Barbu
Original assignee: Nokia Solutions And Networks Oy
Priority date: 2022-12-01
Filing date: 2022-12-01
Publication date: 2024-06-06

Abstract

According to an aspect, there is provided an apparatus for performing the following. The apparatus monitors a resource pool for direct terminal-device-to- terminal-device transmissions by a plurality of terminal devices and use of buffer bands for the direct terminal-device-to-terminal device transmissions. The apparatus selects a resource for transmission from the resource pool and dimensions at least one buffer band for the resource based on results of the monitoring for avoiding or at least reducing overlap of planned transmissions in time and frequency. The at least one buffer band comprises at least one of a lower buffer band or an upper buffer band. The apparatus causes direct terminal-device-to-terminal-device transmission of a signal using the resource while applying the at least one buffer band, wherein the signal comprises information on the at least one buffer band.

Description

ADAPTIVE BUFFER BANDS FOR DIRECT TERMINAL-DEVICE-TO-TERMINAL-DEVICE COMMUNICATION

TECHNICAL FIELD

Various example embodiments relate to wireless communications.

BACKGROUND

Sidelink (SL) is a communication paradigm in which terminal devices are able to communicate with each other directly without having to relay data via an access node (i.e., direct terminal-device-to-terminal-device communication is enabled). Sidelink may be employed, for example, by terminal devices in a particular subnetwork for communication with other terminal devices in that subnetwork. From a resource use efficiency perspective, it is desirable that all such transmissions (including transmissions taking place in different subnetworks) take place over the same spectrum, for example, to avoid resource partitioning. However, different communication links in different subnetworks will have different communication ranges associated with them which, in turn, require use of different transmit power levels. Therefore, when mixing into the same resource pool, resources associated with transmissions in multiple different subnetworks, it may be expected that different transmit powers are employed within the resource pool. This will cause the in-band emissions (IBE) to severely impact the reception performance due to imperfect filters at both the transmitter and receiver sides.

BRIEF DESCRIPTION

According to an aspect, there is provided the subject matter of the independent claims. Embodiments are defined in the dependent claims. The scope of protection sought for various embodiments is set out by the independent claims.

The embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims may be interpreted as examples useful for understanding various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, some example embodiments will be described with reference to the accompanying drawings, in which

Figure 1 illustrates an example of a communications system to which embodiments may be applied; Figures 2A and 2B illustrate, respectively, an exemplary resource pool for multiple subnetworks and an exemplary communication scenario illustrating disadvantages of prior art solutions;

Figures 3 to 6 illustrate examples of processes according to embodiments;

Figure 7 illustrates a dynamic buffer band concept according to embodiments on top of existing subchannel definitions of sidelink; and

Figure 8 illustrates an exemplary apparatus according to embodiments.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

In the following, different exemplifying embodiments will be described using, as an example of an access architecture to which the embodiments may be applied, a radio access architecture based on long term evolution advanced (LTE Advanced, LTE-A) or new radio (NR, 5G), without restricting the embodiments to such an architecture, however. It is obvious for a person skilled in the art that the embodiments may also be applied to other kinds of communications networks having suitable means by adjusting parameters and procedures appropriately. Some examples of other options for suitable systems are the universal mobile telecommunications system (UMTS) radio access network (UTRAN or E-UTRAN), longterm evolution (LTE, the same as E-UTRA), wireless local area network (WLAN or WiFi), worldwide interoperability for microwave access (WiMAX), Bluetooth®, personal communications services (PCS), ZigBee®, wideband code division multiple access (WCDMA), systems using ultra-wideband (UWB) technology, sensor networks, mobile ad-hoc networks (MANETs) and Internet Protocol multimedia subsystems (IMS) or any combination thereof.

As used herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

Figure 1 depicts examples of simplified system architectures only showing some elements and functional entities, all being logical units, whose implementation may differ from what is shown. The connections shown in Figure 1 are logical connections; the actual physical connections may be different. It is apparent to a person skilled in the art that the system typically comprises also other functions and structures than those shown in Figure 1.

The embodiments are not, however, restricted to the system given as an example but a person skilled in the art may apply the solution to other communication systems provided with necessary properties.

The example of Figure 1 shows a part of an exemplifying radio access network. Figure 1 shows user devices 100 and 102 (equally called terminal devices) configured to be in a wireless connection on one or more communication channels in a cell with an access node (such as (e/g)NodeB) 104 providing the cell. An eNodeB or a gNodeB, are herein collectively referred to as (e/g)NodeB. The physical link from a user device to a (e/g)NodeB is called uplink or reverse link and the physical link from the (e/g)NodeB to the user device is called downlink or forward link. It should be appreciated that (e/g)NodeBs or their functionalities may be implemented by using any node, host, server or access point etc. entity suitable for such a usage.

A communications system typically comprises more than one (e/g)NodeB in which case the (e/g)NodeBs may also be configured to communicate with one another over links, wired or wireless, designed for the purpose. These links may be used for signalling purposes. The (e/g)NodeB is a computing device configured to control the radio resources of communication system it is coupled to. The NodeB may also be referred to as a base station, an access point or any other type of interfacing device including a relay station capable of operating in a wireless environment. The (e/g)NodeB includes or is coupled to transceivers. From the transceivers of the (e/g) NodeB, a connection is provided to an antenna unit that establishes bi-directional radio links to user devices. The antenna unit may comprise a plurality of antennas or antenna elements. The (e/g)NodeB is further connected to core network 110 (CN or next generation core NGC). Depending on the system, the counterpart on the CN side can be a serving gateway (S-GW, routing and forwarding user data packets), packet data network gateway (P-GW), for providing connectivity of user devices (UEs) to external packet data networks, or mobile management entity (MME), etc.

The user device (also called UE, user equipment, user terminal or terminal device) illustrates one type of an apparatus to which resources on the air interface are allocated and assigned, and thus any feature described herein with a user device may be implemented with a corresponding apparatus, such as a relay node. An example of such a relay node is a layer 3 relay (self-backhauling relay) towards the base station.

The user device typically refers to a portable computing device that includes wireless mobile communication devices operating with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: a mobile station (mobile phone), smartphone, personal digital assistant (PDA), handset, wearable device using a wireless modem (alarm or measurement device, etc.), laptop and/or touch screen computer, tablet, game console, notebook, and multimedia device. It should be appreciated that a user device may also be a nearly exclusive uplink only device, of which an example is a camera or video camera loading images or video clips to a network. A user device may also be a device having capability to operate in Internet of Things (loT) network which is a scenario in which objects are provided with the ability to transfer data over a network without requiring human-to-human or human-to- computer interaction. The user device (or in some embodiments a layer 3 relay node) is configured to perform one or more of user equipment functionalities. The user device may also be called a subscriber unit, mobile station, remote terminal, access terminal, user terminal or user equipment (UE) just to mention but a few names or apparatuses.

Various techniques described herein may also be applied to a cyber-physical system (CPS) (a system of collaborating computational elements controlling physical entities). CPS may enable the implementation and exploitation of massive amounts of interconnected ICT devices (sensors, actuators, processors microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber physical systems, in which the physical system in question has inherent mobility, are a subcategory of cyberphysical systems. Examples of mobile physical systems include mobile robotics and electronics transported by humans or animals.

It should be understood that, in Figure 1, user devices are depicted to include 2 antennas only for the sake of clarity. The number of reception and/or transmission antennas may naturally vary according to a current implementation.

Additionally, although the apparatuses have been depicted as single entities, different units, processors and/or memory units (not all shown in Figure 1) may be implemented.

5G enables using multiple input - multiple output (M1M0) antennas, many more base stations or nodes than the LTE (a so-called small cell concept), including macro sites operating in co-operation with smaller stations and employing a variety of radio technologies depending on service needs, use cases and/or spectrum available. 5G mobile communications supports a wide range of use cases and related applications including video streaming, augmented reality, different ways of data sharing and various forms of machine type applications, including vehicular safety, different sensors and real-time control. 5G is expected to have multiple radio interfaces, namely below 6GHz, cmWave and mmWave, and also being integradable with existing legacy radio access technologies, such as the LTE. Integration with the LTE may be implemented, at least in the early phase, as a system, where macro coverage is provided by the LTE and 5G radio interface access comes from small cells by aggregation to the LTE. In other words, 5G is planned to support both inter- RAT operability (such as LTE-5G) and inter-Rl operability (inter-radio interface operability, such as between a below 6GHz radio interface and a cmWave radio interface and/or between a below 6GHz radio interface a cmWave radio interface and an mmWave radio interface). One of the concepts considered to be used in 5G networks is network slicing in which multiple independent and dedicated virtual sub-networks (network instances) may be created within the same infrastructure to run services that have different requirements on latency, reliability, throughput and mobility. The current architecture in LTE networks is fully distributed in the radio and fully centralized in the core network. The low latency applications and services in 5G require to bring the content close to the radio which leads to local break out and multiaccess edge computing (MEC). 5G enables analytics and knowledge generation to occur at the source of the data. This approach requires leveraging resources that may not be continuously connected to a network such as laptops, smartphones, tablets and sensors. MEC provides a distributed computing environment for application and service hosting. It also has the ability to store and process content in close proximity to cellular subscribers for faster response time. Edge computing covers a wide range of technologies such as wireless sensor networks, mobile data acquisition, mobile signature analysis, cooperative distributed peer-to-peer ad hoc networking and processing also classifiable as local cloud/fog computing and grid/mesh computing, dew computing, mobile edge computing, cloudlet, distributed data storage and retrieval, autonomic self-healing networks, remote cloud services, augmented and virtual reality, data caching, Internet of Things (massive connectivity and/or latency critical), critical communications (autonomous vehicles, traffic safety, real-time analytics, time-critical control, healthcare applications).

The communication system is also able to communicate with other networks, such as a public switched telephone network or the Internet 112, or utilize services provided by them. The communication network may also be able to support the usage of cloud services, for example at least part of core network operations may be carried out as a cloud service (this is depicted in Figure 1 by “cloud” 114). The communication system may also comprise a central control entity, or the like, providing facilities for networks of different operators to cooperate for example in spectrum sharing.

Edge cloud may be brought into radio access network (RAN) by utilizing network function virtualization (NVF) and software defined networking (SDN). Using edge cloud may mean access node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head or base station comprising radio parts. It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. Application of cloudRAN architecture enables RAN real time functions being carried out at the RAN side (in a distributed unit, DU 104) and non-real time functions being carried out in a centralized manner (in a centralized unit, CU 108).

It should also be understood that the distribution of labor between core network operations and base station operations may differ from that of the LTE or even be non-existent. Some other technology advancements probably to be used are Big Data and all-lP, which may change the way networks are being constructed and managed. 5G (or new radio, NR) networks are being designed to support multiple hierarchies, where MEC servers can be placed between the core and the base station or nodeB (gNB). It should be appreciated that MEC can be applied in 4G networks as well.

5G may also utilize satellite communication to enhance or complement the coverage of 5G service, for example by providing backhauling. Possible use cases are providing service continuity for machine-to-machine (M2M) or Internet of Things (loT) devices or for passengers on board of vehicles, or ensuring service availability for critical communications, and future railway/maritime/aeronautical communications. Satellite communication may utilize geostationary earth orbit (GEO) satellite systems, but also low earth orbit (LEO) satellite systems, in particular mega-constellations (systems in which hundreds of (nano)satellites are deployed). Each satellite 106 in the mega-constellation may cover several satellite-enabled network entities that create on-ground cells. The on- ground cells may be created through an on-ground relay node 104 or by a gNB located on-ground or in a satellite.

5G may also utilize unlicensed spectrum, similar to WLAN or Multefire. 5G operating in unlicensed spectrum is also referred to as NR-U.

It is obvious for a person skilled in the art that the depicted system is only an example of a part of a radio access system and in practice, the system may comprise a plurality of (e/g)NodeBs, the user device may have an access to a plurality of radio cells and the system may comprise also other apparatuses, such as physical layer relay nodes or other network elements, etc. At least one of the (e/g)NodeBs may be a Home(e/g)nodeB. Additionally, in a geographical area of a radio communication system a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. Radio cells may be macro cells (or umbrella cells) which are large cells, usually having a diameter of up to tens of kilometers, or smaller cells such as micro-, femto- or picocells. The (e/g)NodeBs of Figure 1 may provide any kind of these cells. A cellular radio system may be implemented as a multilayer network including several kinds of cells. Typically, in multilayer networks, one access node provides one kind of a cell or cells, and thus a plurality of (e/g)NodeBs are required to provide such a network structure.

For fulfilling the need for improving the deployment and performance of communication systems, the concept of “plug-and-play” (e/g)NodeBs has been introduced. Typically, a network which is able to use “plug-and-play” (e/g)NodeBs, includes, in addition to Home (e/g)NodeBs (H(e/g)nodeBs), a home node B gateway, or HNB-GW (not shown in Figure 1). A HNB Gateway (HNB-GW), which is typically installed within an operator’s network may aggregate traffic from a large number of HNBs back to a core network.

6G networks are expected to adopt flexible decentralized and/or distributed computing systems and architecture and ubiquitous computing, with local spectrum licensing, spectrum sharing, infrastructure sharing, and intelligent automated management underpinned by mobile edge computing, artificial intelligence, short-packet communication and blockchain technologies. Key features of 6G will include intelligent connected management and control functions, programmability, integrated sensing and communication, reduction of energy footprint, trustworthy infrastructure, scalability and affordability. In addition to these, 6G is also targeting new use cases covering the integration of localization and sensing capabilities into system definition to unifying user experience across physical and digital worlds.

The terminal devices 100, 102 may be configured for performing direct terminal-device-to-terminal-device communication using sidelink (e.g., NR or 6G sidelink) or other direct terminal-device-to-terminal-device communication scheme. In other words, the terminal devices 100, 102 are able to communicate with each other directly without having to relay data via an access node. The terminal devices 100, 102 may belong to a particular subnetwork or subnetworks.

The following definitions may apply for terminal-device-to-terminal-device communication as discussed here and in the following. The direct terminal-device-to- terminal-device communication may be enabled by reserving a first set of resources for transferring control information, over a control information channel and reserving a second set of resources for transferring data, over a data information channel. The term “resource” as used here and in the following may correspond to a physical resource block (PRE) or a set of PRBs. The communication link between two terminal devices may or may not rely on sending known raw signals for learning the wireless communication channel between the two devices. Moreover, the resources used by the control and data channels may be partly/totally overlapping or completely disjoint (i.e., completely nonoverlapping), but their configuration may be fully known by both communication ends.

Direct terminal-device-to-terminal-device communication (e.g., NR or 6G sidelink) may be employed, for example, by terminal devices (e.g., terminal device 100, 102) in a particular subnetwork for communication with other terminal devices in that subnetwork. This communication may be expected to occur between terminal devices near each other, ranging from a distance of less than 1 meter (e.g., for wearable terminal devices in a body network) to several meters (e.g., for terminal devices for in-car communication and smart home applications). From a resource use efficiency, it is desirable, for example, to avoid resource partitioning that all this communication taking place in multiple different subnetworks takes place over the same frequency spectrum, i.e., using the same resource pool.

Figure 2A shows an example of one such resource pool comprising resources allocated to three different subnetworks. Each resource (e.g., a PRE) of the resource pool corresponds to a reserved subchannel for at least one of the three subnetworks. A subchannel may be equally called a sub-channel, and a subnetwork may be equally called a sub-network. Notably, one of the resources of the resource pool in this example is reserved both for subnetwork 1 and subnetwork 2.

In general, the configuration of resources in a (sidelink) resource pool may define the minimum information required for a receiving terminal device to be able to decode a transmission. This minimum information may comprise, e.g., the number of subchannels, the number of physical resource blocks per subchannels, the number of symbols in the physical sidelink control channel (PSCCH) and which slots have a physical sidelink feedback channel (PSFCH) (being a channel for transmitting HARQ feedback from a receiving terminal device to a transmitting terminal device on the sidelink for a unicast or groupcast communication).

Different communication links in different subnetworks may have different communication ranges associated with them. This necessitates use of different transmit power levels for the different subnetworks. Therefore, when mixing resources for these different communication links associated with different transmit power levels into the same resource pool, as illustrated in Figure 2A, it is expected that these will have different transmission powers. This will make the in-band emissions (1BE) start to severely impact the reception performance, due to imperfect filters at both the transmitter and receiver sides. For example, it may take several PRBs (e.g., 5 PRBs) for an 1BE mask to decay from full transmit power to a transmit power baseline of -10 dB.

Figure 2B is a schematic Figure relating to a scenario where power is received, in a terminal device, via three adjacent subchannels with differing transmit power levels (and thus also different receipt power levels). Specifically, Figure 2B plots received power (P) against PRBs transmitted over three adjacent subchannels with indices n, n+1 and n+2 (where n may have any arbitrary integer value). Here, the subchannel n+1 corresponds to the desired transmission while the subchannel n is another transmission in the same subnetwork as the desired transmission and the subchannel n+2 is a transmission from another subnetwork. Due to 1BE and imperfect Rx filtering, there is significant overlap between the three transmissions, as indicated with dashed ellipses. The reception of the desired transmission on subchannel n is, thus, degraded due to interference caused by transmissions in adjacent subchannels n and n+2.

From a resource use efficiency perspective, it is desirable that all such transmissions (including transmissions taking place in different subnetworks) take place over the same frequency spectrum, for example, to avoid resource partitioning. However, different communication links in different subnetworks will have different communication ranges associated with them which, in turn, require use of different transmit power levels. Therefore, when mixing into the same resource pool, resources associated with transmissions in multiple different subnetworks, it may be expected that different transmit powers are employed within the resource pool. This will cause the in- band emissions BE) to severely impact the reception performance due to imperfect filters at both the transmitter and receiver sides. The severity of this interference is dependent on reception power in those subchannels, which for the targeted mixed link range cases (e.g., when the communications belong to different sub-networks but still coexist in the same resources) can be significant, as the close proximity terminal devices will be using low transmit power, while the longer-range terminal devices will be using higher transmit power.

In a vehicle-to-everything (V2x) setting, it may be expected that vehicles are separated by at least a few meters, therefore the out-of-band (OBE) and in-band (1BE) emissions of one terminal device may, at least in some cases, be made negligible by the distance between terminal devices i.e., the OBE and 1BE signals are sufficiently attenuated so that they do not cause interference at another device which uses adjacent PRBs. However, in a subnetwork, due to the proximity of the terminal devices relative to each other and use of a combination of communication links with different power levels especially when these belong to different sub-networks, the OBE/1BE emissions cannot be neglected anymore and subnetwork terminal devices that use adjacent spectral resources can cause non-negligible adjacent channel interference.

One way to avoid the aforementioned interference problem would be to configure a static buffer band between subchannels. However, this approach is not resource efficient since the impact of OBE and 1BE is highly dependent on where the different transmitting terminal devices are relative to a given receiving terminal device. Such static approach would require dimensioning the buffer band to meet the requirements of the worst case scenario. As a motivating example, consider a resource pool with 10 subchannels and the need to separate the subchannels by 5 PRBs, this would lead in the worst case scenario to 50 PRBs not being used.

The embodiments to be discussed below seek to overcome or at least alleviate at least some of the problems described above. Namely, the embodiments enable a terminal device to adaptively and on-demand to learn an optimal setting for buffer band(s) and to activate the buffer band(s) dynamically.

Figure 3 illustrates a process according to embodiments for carrying out direct terminal-device-to-terminal-device transmission. The illustrated process may be carried out by a terminal device such as one of terminal devices 100, 102 of Figure 1 or a particular unit or part (e.g., a computing device) comprised in said terminal device or a device communicatively connected to said terminal device. The terminal device may be assumed to be configured for direct terminal-device-to-terminal-device communication at least with one other terminal device. In the following, the entity carrying out the illustrated process is called simply an apparatus without loss of generality. It should be noted that neither the transmitting nor the receiving terminal device may know a priori which other direct terminal-device-to-terminal device links are currently active in any adjacent subchannel. Thus, the terminal devices may not be a priori informed about IBE or OBE levels. As a result, neither device knows in advance if and how large buffer bands should be used to pad their direct link and thus avoid being affected and/or creating IBE/OBE.

Referring to Figure 3, the apparatus initially monitors, in block 301, a resource pool for planned direct terminal-device-to-terminal-device transmissions (e.g., sidelink transmissions) by a plurality of terminal devices and associated use of buffer bands for the planned direct terminal-device-to-terminal device transmissions. The resource pool may comprise one or more resources or a plurality of resources. The term “resource” as used here and in the following may correspond to a PRB or a set of PRBs. The monitoring in block 301 may comprise intra and/or inter subnetwork monitoring.

In some embodiments, the resource pool may comprise resources for a plurality of subnetworks all or at least some which are associated with different transmit power levels or different average or median transmit power levels, similar to as discussed in connection with Figures 2A and 2B. Each of the plurality of subnetworks may be associated with one or more subchannels.

In some embodiments, each or at least one of the resources of the resource pool may comprise at least one of the following: a set of one or more contiguous PRBs in a single time slot; a set of one or more contiguous PRBs in multiple consecutive time slots; an interlace of one or more PRBs in a single time slot or in multiple consecutive time slots; or a set of one or more interlaces of PRBs in a single time slot or in multiple consecutive time slots.

In some embodiments, the monitoring in block 301 may comprise collecting information on reserved resources of the resource pool (e.g., by receiving one or more signals indicating reservation of at least one resource from one or more terminal device) and/or performing one or more direct terminal-device-to-terminal-device reference signal received power (RSRP) measurements relating to the resource pool. Reserved resources of the resource pool may be indicated to the apparatus as control information such as sidelink control information (SCI) via PSCCH. The one or more direct terminal- device-to-terminal-device reference signal received power measurements may comprise or consist of one or more sidelink reference signal received power (SL-RSRP) measurements.

In some embodiments, the monitoring in block 301 may comprise at least receiving, from a first set of one or more terminal devices, one or more first (direct terminal-device-to-terminal-device) transmissions indicating that one or more planned direct terminal-device-to-terminal device transmissions of the one or more terminal devices in the first set need to be protected by at least one of a lower buffer band or an upper buffer band. Additionally or alternatively, the monitoring in block 301 may comprise receiving, from a second set of one or more terminal devices, one or more second (direct terminal-device-to-terminal-device) transmissions indicating that one or more lower buffer bands and/or one or more upper buffer bands are to be applied, by the one or more terminal devices in the second set, for one or more respective planned direct terminal-device-to-terminal device transmissions of the one or more terminal devices in the second set. The first and second sets of one or more terminal devices may be disjoint sets of terminal devices, or one or more terminal devices may belong to both of the first and second sets. The apparatus may store, to at least one memory, any of the received information.

The apparatus selects, in block 302, a resource for (direct terminal-device-to- terminal-device) transmission from the resource pool. The selecting in block 302 may be based, for example, on a size of required upper and/or lower buffer bands. Alternatively or additionally, the selecting in block 302 may be based on an amount of expected out-of- band emissions and/or in-band emissions from one or more adjacent subchannels. The selected resource may correspond to one or more subchannels. Here, the number of the one or more subchannels may be dependent on need for implementing at least one buffer band (see block 303).

For example, the apparatus may select, in block 302, the resource which requires the smallest buffer band or bands. Alternatively, the apparatus may select the resource to be a resource satisfying one or more pre-defined criteria (e.g., for the size of the buffer band or bands).

In some embodiments, the apparatus may exclude, in the selecting of the resource in block 302, any resources for which expected out-of-band emissions and/or in-band emissions from one or more adjacent subchannels (in the same or different subnetwork as the desired transmission) exceed a pre-defined level based on results of the monitoring.

In some embodiments, the resource selected from the resource pool in block 302 may comprise at least one of the following: a set of one or more contiguous PRBs in a single time slot; a set of one or more contiguous PRBs in multiple consecutive time slots; an interlace of one or more PRBs in a single time slot or in multiple consecutive time slots; or a set of one or more interlaces of PRBs in a single time slot or in multiple consecutive time slots. The apparatus dimensions, in block 303, at least one buffer band for the resource based on results of the monitoring for avoiding or at least reducing overlap of planned transmissions in time and frequency. The at least one buffer band comprises at least one of a lower buffer band or an upper buffer band. In some embodiments, the at least one buffer band may consist of the lower buffer band or the upper buffer band. Each of the at least one buffer band may have a size of one or more subcarriers. The dimensioning in block 303 may comprise selecting a (band)width for the at least one buffer band.

The term “lower buffer band” may be defined, here and in the following, as a buffer frequency band preceding in frequency the desired data transmission. The lower buffer band enables the transmission (e.g., a physical sidelink control channel, PSCCH, transmission) to be protected from the emissions taking place in a lower adjacent subchannel. The number of resources (e.g., PRBs) that may be allocated to the lower buffer band may depend on the emission rejection mask used at the receiving terminal device.

The term “upper buffer band” may be defined, here and in the following, as a buffer frequency band following in frequency the desired data transmission. The upper buffer band enables the transmitting terminal device to protect a potential transmission (e.g., a PSCCH transmission) in the adjacent upper channel from its own transmission. The number of resources (e.g., PBRs) that may be allocated to the upper buffer band may depend on the transmission emission mask of the transmitting terminal device as well as on the transmit power of the transmitting terminal device.

In general, the purpose of the lower and upper bands is to prevent the problem discussed in connection with Figure 2B, that is, overlapping of the desired data transmission transmitted over a first subchannel with transmissions over adjacent subchannels in the same subnetwork and /or in a different subnetwork. It should be noted an upper buffer band for a first subchannel may act as a lower buffer band for a second subchannel following and being adjacent to the first subchannel.

It should be noted that, in some embodiments, the transmitting terminal device may only be able to impact the use of an upper buffer band, while the lower dynamic buffer band use may be dependent on the transmission taking place in the lower adjacent subchannel also applying a dynamic upper buffer band. This may apply, for example, when (NR or 6G) sidelink communication is employed.

The apparatus causes, in block 304, transmission of a signal (by the terminal device) using the resource while applying the at least one buffer band. Here, the signal comprises information on the at least one buffer band. The signal may be specifically a radio signal or a data radio signal. The signal may comprise the information on the at least one buffer band as control information (e.g., as sidelink control information, SCI, in sidelink-based embodiments). The signal may be transmitted to a terminal device belonging to the same subnetwork as the terminal device associated with the apparatus. The transmission in block 304 may be, e.g., a PSCCH transmission.

The information on the at least one buffer band may comprise at least information indicating existence of the at least one buffer band. For example, said information may comprise a single bit indicating an existence of an upper buffer band and/or a single bit indicating an existence of a lower buffer band. In other embodiments, more detailed information regarding the at least one buffer band or at least one of the at least one buffer band (if both lower and upper buffer bands are used) may be provided. In other embodiments, said information may comprise multiple bits.

In some embodiments, the information on the at least one buffer band may comprise information on one or more (buffer band) types of the at least one buffer band. A type of a buffer band may be associated at least with (or mapped at least to) a range of emission levels supported by that buffer band. In other words, the type of the buffer band may (uniquely) define the range of emission levels supported by that buffer band. In general, a plurality of different types for upper and/or lower buffer bands maybe defined. Each of the plurality of different types of buffer bands may correspond to a certain emission level interval supported by a buffer band of that type. For example, type 1 may be associated with low emission levels so that buffer bands of type 1 support emission levels from -oo dB to -10 dB while type 2 may be associated with slightly higher emission levels so that buffer bands of type 2 support emission levels from -10 dB to -5 dB (or in practice -oo dB to -5 dB) and so on. In other words, subnetwork elements utilizing a buffer band of type k (e.g., receiving data in the buffer band of type k) may be capable of interference rejection at least as long as the interfering signal power is larger than or equal to a pre-defined lower limit value Pi_ow and smaller than or equal to a pre-defined higher limit value Phigh.

As described above, each of the at least one buffer band in block 204 may have a size of one or more subcarriers. The subcarriers of a given buffer band may be associated with one or more different types of buffer bands. For example, an upper buffer band of size L subcarriers (L being an integer larger than one) may be associated with a buffer of type 1 for subcarriers belonging to a first set of subcarriers and a buffer of type 2 for subcarriers belonging to a second set of subcarriers. Thus, in summary, the information on the at least one buffer band transmitted in block 304 comprises information on one or more types of the at least one buffer band, where each of the one or more types of the at least one buffer band is associated at least with a range of emission levels supported, fully or partly, by at least one of the at least one buffer band.

Figure 4 illustrates another process according to embodiments for carrying out direct terminal-device-to-terminal-device transmission. The illustrated process may be carried out by a terminal device such as one of terminal devices 100, 102 of Figure 1 or a particular unit or part (e.g., a computing device) comprised in said terminal device or a device communicatively connected to said terminal device. In the following, the entity carrying out the illustrated process is called simply an apparatus without loss of generality.

The process of Figure 4 may be considered a more detailed implementation of the process of Figure 3. Thus, any of the definitions provided in connection with Figure 3 may apply, mutatis mutandis, for the process of Figure 4. Actions pertaining to blocks 401, 405, 408 of Figure 4 may be carried out as described in connection with blocks 301, 303, 304 of Figure 3 above and are thus not discussed here in detail for brevity.

Referring to Figure 4, following the monitoring of the resource pool in block 401, the apparatus selects, in block 402, a set of candidate resources for (direct terminal- device-to-terminal-device) transmission from the resource pool. The selection of the set of candidate resources may be made, e.g., based on results of the monitoring carried out in block 401.

Similar to as described above in connection with block 301 of Figure 3, in some embodiments, the monitoring in block 401 may comprise collecting information on reserved resources of the resource pool (e.g., by receiving one or more signals indicating reservation of at least one resource from one or more terminal device) and/or performing one or more direct terminal-device-to-terminal-device (e.g., sidelink) RSRP measurements relating to the resource pool. The selection of the set of candidate resources may be made at least based on the reserved resources and/or results of the one or more direct terminal-device-to-terminal-device RSRP measurements. Namely, the selection may be made so that the set of candidate resources comprises no reserved resources and/or comprises resources for which the direct terminal-device-to-terminal- device RSRP (or an average thereof) satisfies one or more pre-defined criteria (e.g., exceeds a pre-defined threshold).

In some alternative embodiments, all of the resources in the resource pool are considered candidate resources for transmission. In other words, the resource pool is the same as the set of candidate resources. In such embodiments, block 402 may be omitted.

The apparatus ranks, in block 403, the candidate resources in the set based on 1) a size (or equally length) of required upper and/or lower buffer bands or 2) an amount of expected out-of-band emissions and/or in-band emissions from one or more adjacent subchannels.

Regarding the first alternative, resources without a buffer band may be preferred (i.e., ranked higher), in the ranking, in relation to resources that require upper and/or lower buffer band(s). Further regarding the first alternative, resources requiring upper and/or lower buffer band(s) of a small size may be preferred, in the ranking, in relation to resources that require upper and/or lower buffer band(s) with a large size. The ranking based on the size of both required upper and lower buffer bands may be more specifically based, e.g., on a combined size of the upper and lower buffer bands or an average size of the upper and lower buffer bands.

Regarding the second alternative, resources associated with a lower amount of expected out-of-band emissions and/or in-band emissions may be preferred (i.e., ranked higher), in the ranking, over resources associated with a higher amount of expected out-of-band emissions and/or in-band emissions. The amount of expected out- of-band emissions and/or in-band emissions from one or more adjacent subchannels may be determined based on results of the monitoring carried out in block 401.

In some embodiments, the ranking in block 403 may be based on a metric whose value is dependent on the size (or width) of the required upper and/or lower buffer bands and the amount of expected out-of-band emissions and/or in-band emissions from one or more adjacent subchannels.

The apparatus selects, in block 404, a resource for (direct terminal-device-to- terminal-device) transmission based on the ranked set of candidate resources (determined in block 403). The apparatus may select, in block 404, a resource belonging to n highest ranked candidate resources (n being a pre-defined positive integer). In some embodiments, the apparatus may select, in block 404, the highest ranked candidate resource.

As described above, following the selection of the resource in block 404, the apparatus dimensions, in block 405, at least one buffer band for the resource based on results of the monitoring for avoiding or at least reducing overlap of planned transmissions in time and frequency and causes, in block 406, direct terminal-device-to- terminal-device transmission of a signal using the resource while applying the at least one buffer band, similar to as described in connection with blocks 303-304 of Figure 3.

After the dimensioning in block 405, the apparatus continues, in block 406, the monitoring of the resource pool and the associated use of buffer bands (i.e., the monitoring carried out originally in block 401).

Then, the apparatus determines, in block 407, based on results of the continued monitoring whether or not the at least one buffer band is still sufficient for avoiding or reducing overlap with planned transmissions in time and frequency. In other words, the apparatus determines, in block 407, whether or not at least one new transmission received after the original monitoring in block 401 indicates that there will be a future transmission adjacent in frequency (and time) to the selected resource. Existence of such at least one new transmission may be seen to indicate that the size (or length) of the at least one buffer band may not be sufficient. In response to determining based on the continued monitoring in block 406 that the at least one buffer band is no longer sufficient for avoiding or at least reducing overlap with planned transmissions in time and frequency in block 407, the apparatus repeats the dimensioning of block 405 taking into account both results of the monitoring [of block 401) and results of the continued monitoring [of block 406). Subsequently, the apparatus continues monitoring [again) in block 406 and repeats the check of block 407.

In response to determining based on the continued monitoring in block 406 that the at least one buffer band is still sufficient for avoiding or at least reducing overlap with planned transmissions in time and frequency in block 407, the apparatus causes, in block 408, direct terminal-device-to-terminal-device transmission of a signal using the resource selected in block 404 while applying the at least one buffer band.

In some embodiments, only one of the two additional features of the process of Figure 4 over the process of Figure 3 described, respectively, in connection with blocks 402 to 404 and blocks 406, 407 may be implemented.

Figure 5 illustrates a process according to embodiments for carrying out direct terminal-device-to-terminal-device reception of buffer band information. The illustrated process may be carried out by a terminal device such as one of terminal devices 100, 102 of Figure 1 or a particular unit or part [e.g., a computing device) comprised in said terminal device or a device communicatively connected to said terminal device. The terminal device may be assumed to be configured for direct terminal-device-to-terminal-device communication at least with one other terminal device. In the following, the entity carrying out the illustrated process is called simply an apparatus without loss of generality.

It should be noted that neither the transmitting nor receiving terminal device may know a priori which other direct terminal-device-to-terminal device links are currently active in any adjacent subchannel. Thus, the terminal devices may not be a priori informed about IBE or OBE levels. As a result, neither device knows in advance if and how large buffer bands should be used to pad their direct link and thus avoid being affected and/or creating IBE/OBE.

The process of Figure 5 may be carried out by a receiving terminal device [or a part thereof) following a completion of the process of Figure 3 or 4 by a transmitting terminal device. Thus, any of the definitions provided in connection with Figure 3 or 4 relating to the direct terminal-device-to-terminal-device transmission may apply equally here.

Referring to Figure 5, the apparatus receives, in block 501, a signal from a terminal device as a direct terminal-device-to-terminal-device [e.g., sidelink) transmission. The signal may correspond to the signal transmitted in block 304 of Figure 3 and/or block 408 of Figure 4. Similar to above embodiments, the signal comprises information on at least one buffer band applied to the signal. Moreover, the at least one buffer band comprises at least one of a lower buffer band or an upper buffer band. In some embodiments (e.g., in some sidelink-based embodiments), the at least one buffer band may comprise at least or exclusively the upper buffer band. The signal may comprise the information on the at least one buffer band applied to the signal as control information (e.g., as SCI in sidelink-based embodiments). The information on the at least one buffer band may comprise at least information indicating existence of the at least one buffer band, as described above. Optionally, the information on the at least one buffer band may comprise information on one or more types of the at least one buffer band, where each of the one or more types of the at least one buffer band may be associated at least with a range of emission levels supported, fully or partly, by at least one of the at least one buffer band.

The apparatus decodes, in block 502, the signal taking into account the information on the at least one buffer band. The signal may be a data signal or a data radio signal. To take the information on the at least one buffer band into account in the decoding, the apparatus may, e.g., exclude, in block 502, any OFDM symbols overlapping in the at least one buffer band (or one of the upper and lower buffer bands) from being included in the decoding process and, thus, reject noise/interference from those OFDM symbols. The apparatus may also carry out, in block 502, demodulation and/or demapping for the signal (before the decoding).

According to an embodiment, there is provided a system comprising an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform the process described in connection with Figure 3 or 4 and an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform the process described in connection with Figure 5.

According to an embodiment, there is provided a system comprising an apparatus comprising means for performing the process described in connection with Figure 3 or 4 and an apparatus comprising means for performing the process described in connection with Figure 5.

Figure 6 illustrates processes and signaling according to embodiments for carrying out sidelink transmission and reception (e.g., NR or 6G sidelink transmission and reception). The illustrated process may be carried out by two terminal devices such as terminal devices 100, 102 of Figure 1 or a particular units or parts (e.g., computing device) comprised in said two terminal devices or two devices communicatively connected to said two terminal devices. In the following, the entities carrying out the illustrated process are called firstand second terminal devices without loss of generality. The processes and signaling depicted in Figure 6 may correspond to a particular more detailed sidelink-based embodiment of the processes of Figure 3 or 4 and Figure 5. Therefore, any of the definitions and features discussed in connection with Figures 3 to 5 may apply also here, unless otherwise explicitly stated.

Referring to Figure 6, the first terminal device monitors, in block 601, a sidelink resource pool for sidelink transmissions by a plurality of terminal devices and associated use of buffer bands for the sidelink transmissions. The monitored SL transmissions relating to the resource pool indicate future (or planned) SL transmissions. The resources in sidelink resource pool may be defined as described in connection with block 301 of Figure 3.

Said monitored SL transmission in block 601 may comprise one or more longterm transmissions (e.g., transmission relating to a periodic configuration of transmissions) and one or more short-term (re)transmissions (i.e., transmission, e.g., within the next 32 slots). The one or more short-term transmission may be associated with both periodic and aperiodic transmissions.

The monitoring in block 601 may comprise receiving, from one or more terminal devices, one or more (SL) transmissions indicating that one or more planned SL transmissions of the one or more terminal devices need to satisfy one or more lower buffer band requirements. In other words, the monitored SL transmissions (or at least some of them) in block 601 may indicate (i.e., comprise information on) their lower buffer band requirement(s). The indication maybe provided as control information (e.g., as SCI). Said one or more lower buffer band requirement may be derivable by these transmitting terminal devices, before the corresponding SL transmission, based on their own emission rejection mask characteristics. The emission rejection mask characteristics may be based, e.g., on RAN4 requirements. The emission rejection mask characteristics may be identified, by the transmitting terminal devices, by means of different profiles or categories. These profiles or categories indicate the characteristics of the one or more filters applied at the transmitter and receiver sides, e.g., in terms of attenuation (in dB) in relation to the center frequency of interest. Additionally or alternatively, said one or more lower buffer band requirements may be derivable, by the SL-capable terminal devices, based on observations of the 1BE and/or OBE from other SL-capable terminal devices when said SL-capable terminal devices are acting in the role of a receiving terminal device for either sensing or actual reception of SL payload.

Additionally or alternative, the monitoring in block 601 may comprise detecting 1BE and/or OBE from each or at least one of the monitored SL transmissions. The 1BE and/or 1BE may be detected for one or more subchannels. The first terminal device may, subsequently, determine one or more lower buffer band requirements of one or more subchannels adjacent to one or more subchannels used for the one or more transmissions based on the 1BE and/or OBE.

Thereafter, the first terminal device selects or compiles, in block 602, a set of candidate resources for transmission from the resource pool based on results of the monitoring. Here, the set of candidate resources may correspond to a single slot. The set of candidate resources may correspond to resource within a particular selection window.

The selecting of the set of candidate resources in block 602 may comprise, if the detected amount of expected 1BE and/or OBE from at least one adjacent subchannel exceeds a pre-defined level for a subchannel, excluding said subchannel from the set of candidate resources.

The first terminal device ranks, also in block 602, the candidate resources in the set based on a size of required upper and/or lower buffer bands or on an amount of expected OBE and/or 1BE from one or more adjacent subchannels.

The first terminal device selects, in block 603, a (single-slot) resource based on the ranked set of candidate resources. The selected resource may be defined as described in connection with block 302 of Figure 3. The selection may be carried out similar to as described, e.g., in connection with block 404 of Figure 4. The number of subchannels selected to be used for the SL transmission (i.e., selected to be comprised in the selected resource) may be affected by the need of an upper dynamic buffer band.

The first terminal device dimensions, in block 604, an upper buffer band for the resource based on results of the monitoring for avoiding or at least reducing overlap of planned SL transmissions in time and frequency.

After the (single-slot) resource selection in block 603 and dimensioning of the associated upper buffer band in block 604, the first terminal device continues, in block 605, to monitor the activity in the resource pool in order to detect if there are new SL transmissions indicating that they will use a resource in an adjacent sub-channel of the single-slot resource selected by the first terminal device which could require repeating the dimensioning of block 604 (similar to as described above in connection with block 406 of Figure 4). In this particular example, it is assumed that no such new SL transmissions are detected and thus there is no need to update the dimensioning of the upper buffer band.

The first terminal device performs, in block 606, one or more preparatory (or preliminary) actions relating to the (upcoming) SL transmission in the selected resource while applying the required upper buffer band. The one or more preparatory actions may comprise preparing transmission of an indication of the upper buffer band (i.e., comprising information on the upper buffer band) at least to the second terminal device. The indication may be communicated as control information, for example, as first stage SCI associated with the upcoming SL transmission of the first terminal device. It should be noted that SCI is commonly split into two stages: a first stage sent on PSCCH, which is associated with a physical sidelink shared channel (PSSCH), and a second stage sent over the corresponding PSSCH. The first stage SCI may comprise, in addition to the aforementioned indication, information on the time and frequency resources, the DMRS configuration of the PSSCH, a modulation and coding scheme (MCS) and/or the PSFCH. The indication may be a simple 1-bit indication (where only one type of upper buffer band can be applied) or n-bits associated with the log2 (of the number of upper buffer band profiles). The indication may enable the second terminal device to take the upper buffer band into account when performing the reception of the associated SL data transmission (on PSSCH). For example, the second terminal device may exclude the OFDM symbols overlapping in the upper buffer band from being included in the decoding process and in this way reject noise/interference from those OFDM symbols.

The first terminal device may implement the upper buffer band in multiple ways. According to the first option, the upper buffer band is implemented so as to be transparent to the encoding, modulation and associated OFDM symbol mapping (and correspondingly also to decoding, demodulation and de-mapping by the second terminal device). Thus, the first terminal device may puncture the OFDM symbols overlapping with the upper buffer band. This enables backward compatibility though it may impact the decoding performance of the second stage SCI.

According to the second option, the upper buffer band is defined so that no OFDM symbols are mapped to any region of the upper buffer band. Thus, in this case, the inclusion of the upper buffer band has an effect on the mapping of the modulated symbols into the OFDM symbol. However, this option ensures that the second stage SCI is not impacted (assuming that the mapping of the OFDM symbols associated with the second stage SCI is changed so as to not take place over the OFDM symbols overlapping with the upper buffer band). This option does have the drawback of not being backwards compatible with the current SL design.

The first terminal device causes, in message 607, SL transmission of a signal using the resource while applying the upper buffer band. The signal comprises information on the upper band buffer band.

The second terminal device receives, in block 608, the SL transmission from the first terminal device. Subsequently, the second terminal device demodulates, demaps and decodes, in block 609, the received SL transmission while taking into account the upper buffer band in use (e.g., the second terminal device may exclude the OFDM symbols overlapping in the upper buffer band from being included in the decoding process and in this way reject noise/interference from those symbols, as described above).

While Figure 6 was described assuming SL communication and use of an upper buffer band, at least some of the features described in connection with Figure 6 (but not in connection with Figures 3 to 5) maybe applicable also to other direct terminal- device-to-terminal-device communication schemes employing upper and/or lower buffer bands. For example, the monitoring of the resource pool and the associated use of buffer bands may comprise, in embodiments described in connection with Figures 3 to 5, receiving, from one or more terminal devices, one or more transmissions indicating that one or more planned direct terminal-device-to-terminal-device transmissions of the one or more terminal devices need to satisfy one or more lower buffer band requirements, similar to block 601 of Figure 6. Additionally or alternatively, the one or more preparatory actions for the upcoming or planned direct terminal-device-to-terminal- device transmission described in connection with block 606. Additionally or alternatively, the definition of the upper buffer band according to the first or second option may be combined, in some embodiments, with the process of any of Figures 3 to 5. Thus, the apparatus carrying out the process of any of Figures 3 to 4 may be configured to implement the at least one buffer band by puncturing any OFDM symbols that overlap with the at least one buffer band or by altering the OFDM symbol mapping so that no OFDM symbols overlap with the at least one buffer band and/or the apparatus of Figure 4 may be configured to exclude any OFDM symbols overlapping with the at least one buffer band from the decoding (based on the received information on the at least one buffer band).

The blocks, related functions, and information exchanges described above by means of Figures 3 to 6 are in no absolute chronological order, and some of them may be performed simultaneously or in an order differing from the given one. Other functions can also be executed between them or within them, and other information may be sent and/or received. Some of the blocks or part of the blocks or one or more pieces of information can also be left out or replaced by a corresponding block or part of the block or one or more pieces of information.

Figure 7 illustrates the dynamic buffer band concept on top of existing NR SL subchannel definitions. The locations of the lower and upper buffer bands are depicted in Figure 7 from the perspective of the transmission taking place in subchannel n. Here, AGC denotes automatic gain control, DMRS denotes the demodulation reference signal, PSCCH denotes the physical sidelink control channel, PSSCH denotes the physical sidelink shared channel and “guard” corresponds to at least one guard symbol. The upper dynamic buffer band enables the transmitting terminal device to protect the transmissions in the adjacent upper channel from its own interference while the lower dynamic buffer band is used for protecting the transmitting terminal device’s own transmission. Note that an important part of the SL transmissions that needs to be protected is the PSCCH which can be activated on a per need basis (i.e., when protection is needed, there is an absence of transmission in a buffer band, while, when this protection is not needed, a transmission is allowed to take place over the buffer band).

Figure 8 illustrates an exemplary apparatus 801 configured to carry out at least some of the actions described above in connection with Figure 1 to 7. The apparatus 801 maybe an electronic device comprising electronic circuitries. The apparatus 801 may be a terminal device (e.g., a terminal device 100 or 102 of Figure 1) or a part thereof (e.g., an integrated circuit or a chip) or a (computing) device connected thereto. The apparatus may be configured or configurable to act as a transmitting (or first) terminal device and/or a receiving (or second) terminal device.

The apparatus 801 may comprise a communication control circuitry 820 such as at least one processor, and at least one memory 830 storing instructions, e.g., a computer program code (software) 831 that, when executed by the at least one processor, cause the apparatus to carry out any one of the embodiments of the apparatus 801 and/or the first or second terminal device described above. Said at least one memory 830 may also comprise at least one database 832.

The memory 830 may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The memory may comprise a learning index, as described in previous embodiments.

The apparatus 801 may further comprise one or more communication interfaces (Tx/Rx) 810 comprising hardware and/or software for realizing communication connectivity according to one or more communication protocols. The one or more communication interfaces 810 may provide the apparatus 801 with communication capabilities to communicate in the cellular communication system and enable communication with network nodes and terminal devices, for example. The one or more communication interfaces 810 may comprise components such as an amplifier, filter, frequency-converter, (de) modulator, and encoder/decoder circuitries and one or more antennas.

Referring to Figure 8, the communication control circuitry 820 may comprise direct UE-to-UE transmission circuitry 821 configured to carry out at least causing direct terminal-device-to-termina-device transmission while applying at least one buffer band. The direct UE-to-UE transmission circuitry 821 may be configured to carry out at least some of the processes of the apparatus or the first terminal device discussed in connection with any of Figures 3, 4 and 6. Additionally or alternatively, the communication control circuitry 820 may comprise direct UE-to-UE reception circuitry 822 configured to carry out at least reception of direct terminal-device-to-terminal- device transmission employing at least one buffer band. The direct UE-to-UE reception circuitry 822 may be configured to carry out at least some of the processes of the apparatus or the second terminal device discussed in connection with any of Figures 5 to 6.

In some alternative embodiments, the communication control circuitry 820 may comprise one of the direct UE-to-UE reception transmission circuitry 821 and the direct UE-to-UE reception circuitry 822.

As used in this application, the term ‘circuitry’ may refer to one or more or all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and/or digital circuitry, and (b) combinations of hardware circuits and software (and/or firmware), such as (as applicable): (i) a combination of analog and/or digital hardware circuit(s) with software/firmware and (ii) any portions of hardware processor(s) with software, including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus, such as a terminal device or an access node, to perform various functions, and (c) hardware circuit(s) and processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g. firmware) for operation, but the software may not be present when it is not needed for operation. This definition of ‘circuitry’ applies to all uses of this term in this application, including any claims. As a further example, as used in this application, the term ‘circuitry’ also covers an implementation of merely a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term ‘circuitry’ also covers, for example and if applicable to the particular claim element, a baseband integrated circuit for an access node or a terminal device or other computing or network device.

In an embodiment, at least some of the processes described in connection with Figures 3 to 6 may be carried out by an apparatus comprising corresponding means for carrying out at least some of the described processes. Some example means for carrying out the processes may include at least one of the following: detector, processor (including dual-core and multiple-core processors), microprocessor, digital signal processor (DSP), controller, micro-controller, receiver, transmitter, encoder, decoder, memory, RAM, ROM, software, firmware, display, user interface, display circuitry, user interface circuitry, user interface software, display software, circuit, antenna, antenna circuitry, application-specific integrated circuit (ASIC), digital signal processing device (DSPD), programmable logic device (PLD) and field programmable gate array (FPGA). For firmware or software, the implementations according to embodiments may be carried out through modules of at least one chipset (procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may be implemented within the processor or externally to the processor. In the latter case, it can be communicatively coupled to the processor via various means, as is known in the art. In an embodiment, the at least one processor, the memory, and the computer program code form processing means or comprises one or more computer program code portions for carrying out one or more operations according to any one of the embodiments of Figures 3 to 6 or operations thereof.

According to an embodiment, there is provided an apparatus (e.g., terminal device or a part thereof or an apparatus connected thereto) comprising means for performing: monitoring a resource pool for direct terminal-device-to-terminal-device transmissions by a plurality of terminal devices and use of buffer bands for the direct terminal-device-to-terminal device transmissions; selecting a resource for transmission from the resource pool; dimensioning at least one buffer band for the resource based on results of the monitoring for avoiding or at least reducing overlap of planned transmissions in time and frequency, wherein the at least one buffer band comprises at least one of a lower buffer band or an upper buffer band; and cause direct terminal-device-to-terminal-device transmission of a signal using the resource while applying the at least one buffer band, wherein the signal comprises information on the at least one buffer band.

According to an embodiment, there is provided an apparatus (e.g., terminal device or a part thereof or an apparatus connected thereto) comprising means for performing: receiving a signal from a terminal device as a direct terminal-device-to- terminal-device transmission, wherein the signal comprises information on at least one buffer band applied to the signal, the at least one buffer band comprising at least one of a lower buffer band or an upper buffer band; and decoding the signal taking into account the information on the at least one buffer band.

Embodiments as described may also be carried out in the form of a computer process defined by a computer program or portions thereof. Embodiments of the methods described in connection with Figures 3 to 6 may be carried out by executing at least one portion of a computer program comprising corresponding instructions. The computer program may be provided as a computer readable medium comprising program instructions stored thereon or as a non-transitory computer readable medium comprising program instructions stored thereon. The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, which may be any entity or device capable of carrying the program. For example, the computer program may be stored on a computer program distribution medium readable by a computer or a processor. The computer program medium may be, for example but not limited to, a record medium, computer memory, read-only memory, electrical carrier signal, telecommunications signal, and software distribution package, for example. The computer program medium may be a non- transitory medium. Coding of software for carrying out the embodiments as shown and described is well within the scope of a person of ordinary skill in the art.

The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

According to an aspect, there is provided a computer program comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: monitoring a resource pool for direct terminal-device-to-terminal-device transmissions by a plurality of terminal devices and use of buffer bands for the direct terminal-device-to-terminal device transmissions; selecting a resource for transmission from the resource pool; dimensioning at least one buffer band for the resource based on results of the monitoring for avoiding or at least reducing overlap of planned transmissions in time and frequency, wherein the at least one buffer band comprises at least one of a lower buffer band or an upper buffer band; and cause direct terminal-device-to-terminal-device transmission of a signal using the resource while applying the at least one buffer band, wherein the signal comprises information on the at least one buffer band.

According to an aspect, there is provided a computer program comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: receiving a signal from a terminal device as a direct terminal-device-to- terminal-device transmission, wherein the signal comprises information on at least one buffer band applied to the signal, the at least one buffer band comprising at least one of a lower buffer band or an upper buffer band; and decoding the signal taking into account the information on the at least one buffer band.

In an embodiment, there is provided a signal with embedded data comprising information on at least one buffer band applied to the signal, wherein the at least one buffer band comprises at least one of a lower buffer band or an upper buffer band. The signal may be defined (and formed) as described in connection with any of the above embodiments. Even though the embodiments have been described above with reference to examples according to the accompanying drawings, it is clear that the embodiments are not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly, and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.

Claims

1. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: monitoring a resource pool for direct terminal-device-to-terminal-device transmissions by a plurality of terminal devices and use of buffer bands for the direct terminal-device-to-terminal device transmissions; selecting a resource for transmission from the resource pool; dimensioning at least one buffer band for the resource based on results of the monitoring for avoiding or at least reducing overlap of planned transmissions in time and frequency, wherein the at least one buffer band comprises at least one of a lower buffer band or an upper buffer band; and cause direct terminal-device-to-terminal-device transmission of a signal using the resource while applying the at least one buffer band, wherein the signal comprises information on the at least one buffer band.

2. The apparatus of claim 1, wherein the resource pool comprises resources for a plurality of subnetworks associated with different transmit power levels or different average or median transmit power levels.

3. The apparatus of claim 1 or 2, wherein resources of the resource pool and/or the selected resource comprise, each, at least one of the following: a set of one or more contiguous physical resource blocks in a single time slot; a set of one or more contiguous physical resource blocks in multiple consecutive time slots; an interlace of physical resource blocks in a single time slot or in multiple consecutive time slots; or a set of one or more interlaces of physical resource blocks in a single time slot or in multiple consecutive time slots.

4. The apparatus according to any preceding claim, wherein the signal comprises the information on the at least one buffer band as control information.

5. The apparatus according to any preceding claim, wherein the monitoring comprises at least: receiving, from a first set of one or more terminal devices, one or more first transmissions indicating that one or more planned direct terminal-device-to-terminal device transmissions of the one or more terminal devices in the first set need to be protected by at least one of a lower buffer band or an upper buffer band; and/or receiving, from a second set of one or more terminal devices, one or more second transmissions indicating that one or more lower buffer bands and/or one or more upper buffer bands are to be applied, by the one or more terminal devices in the second set, for one or more respective planned direct terminal-device-to-terminal device transmissions of the one or more terminal devices in the second set.

6. The apparatus according to any of claims 1 to 4, wherein the at least one buffer band comprises at least the upper buffer band.

7. The apparatus according to any of claims 1 to 4, wherein the at least one buffer band consists of the upper buffer band.

8. The apparatus according to claim 6 or 7, wherein the monitoring comprises: receiving, from one or more terminal devices, one or more transmissions indicating that one or more planned direct terminal-device-to-terminal device transmissions of the one or more terminal devices need to satisfy one or more lower buffer band requirements.

9. The apparatus according to any of claims 6 to 8, wherein the monitoring comprises: detecting out-of-band emissions and/or in-band emissions based on one or more monitored direct terminal-device-to-terminal-device transmissions; and determining one or more lower buffer band requirements of one or more subchannels adjacent to one or more subchannels of the one or more monitored direct terminal-device-to-terminal-device transmissions based on the out-of-band emissions and/or the in-band emissions.

10. The apparatus according to any preceding claim, wherein the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform: selecting a set of candidate resources for transmission from the resource pool; ranking the candidate resources in the set based on a size of required upper and/or lower buffer bands or on an amount of expected out-of-band emissions and/or in-band emissions from one or more adjacent subchannels; and performing the selecting of the resource for transmission based on a ranked set of candidate resources, wherein candidate resources with small buffer bands or a small amount of expected out-of-band emissions and/or in-band emissions are prioritized, in the selecting of the resource, over resources with large buffer bands or a large amount of expected out-of-band emissions and/or in-band emissions.

11. The apparatus according to any preceding claim, wherein the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to exclude, in the selecting of the resource, any resources for which expected out-of-band emissions and/or in-band emissions from one or more adjacent subchannels exceed a pre-defined level based on the results of the monitoring.

12. The apparatus according to any preceding claim, wherein the resource corresponds to one or more subchannels, the number of the one or more subchannels being dependent on the at least one buffer band.

13. The apparatus according to any preceding claim, wherein the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform: continuing, after the dimensioning and before the causing of the direct terminal-device-to-terminal-device transmission, the monitoring of the resource pool and the associated use of buffer bands; and in response to determining based on the continued monitoring that the at least one buffer band is no longer sufficient for avoiding or at least reducing overlap with planned transmissions in time and frequency, repeating the dimensioning taking into account also results of the continued monitoring.

14. The apparatus according to any preceding claim, wherein the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform: implementing the at least one buffer band by puncturing any orthogonal frequency division multiplexing, OFDM, symbols that overlap with the at least one buffer band; or implementing the at least one buffer band by altering the OFDM symbol mapping so that no OFDM symbols overlap with the at least one buffer band.

15. An apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving a signal from a terminal device as a direct terminal-device-to- terminal-device transmission, wherein the signal comprises information on at least one buffer band applied to the signal, the at least one buffer band comprising at least one of a lower buffer band or an upper buffer band; and decoding the signal taking into account the information on the at least one buffer band.

16. The apparatus of claim 15, wherein the signal comprises the information on the at least one buffer band applied to the signal as control information.

17. The apparatus of claim 15 or 16, wherein the at least one memory and the instructions are configured, with the at least one processor, to cause the apparatus to perform: excluding, from the decoding, any orthogonal frequency division multiplexing, OFDM, symbols of the signal overlapping with the at least one buffer band based on the information on the at least one buffer band.

18. The apparatus according to any preceding claim, wherein the information on the at least one buffer band comprises at least information indicating existence of the at least one buffer band.

19. The apparatus according to any preceding claim, wherein the information on the at least one buffer band comprises information on one or more types of the at least one buffer band, each of the one or more types of the at least one buffer band being associated at least with a range of emission levels supported, fully or partly, by at least one of the at least one buffer band.

20. The apparatus according to any preceding claim, wherein the at least one buffer band comprises at least or exclusively the upper buffer band.

21. The apparatus according to any preceding claim, wherein the direct terminal-device-to-terminal-device transmission corresponds to sidelink transmission.

22. A system comprising: the apparatus according to any of claims 1 to 14; and another apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the another apparatus at least to perform: receiving, as the direct terminal-device-to-terminal-device transmission, the signal comprising the information on the at least one buffer band applied to the signal; and decoding the signal taking into account the information on the at least one buffer band.

23. An apparatus comprising means for performing: monitoring a resource pool for direct terminal-device-to-terminal-device transmissions by a plurality of terminal devices and use of buffer bands for the direct terminal-device-to-terminal device transmissions; selecting a resource for transmission from the resource pool; dimensioning at least one buffer band for the resource based on results of the monitoring for avoiding or at least reducing overlap of planned transmissions in time and frequency, wherein the at least one buffer band comprises at least one of a lower buffer band or an upper buffer band; and cause direct terminal-device-to-terminal-device transmission of a signal using the resource while applying the at least one buffer band, wherein the signal comprises information on the at least one buffer band.

24. An apparatus comprising means for performing: receiving a signal from a terminal device as a direct terminal-device-to- terminal-device transmission, wherein the signal comprises information on at least one buffer band applied to the signal, the at least one buffer band comprising at least one of a lower buffer band or an upper buffer band; and decoding the signal taking into account the information on the at least one buffer band.

25. A method comprising: monitoring a resource pool for direct terminal-device-to-terminal-device transmissions by a plurality of terminal devices and use of buffer bands for the direct terminal-device-to-terminal device transmissions; selecting a resource for transmission from the resource pool; dimensioning at least one buffer band for the resource based on results of the monitoring for avoiding or at least reducing overlap of planned transmissions in time and frequency, wherein the at least one buffer band comprises at least one of a lower buffer band or an upper buffer band; and cause direct terminal-device-to-terminal-device transmission of a signal using the resource while applying the at least one buffer band, wherein the signal comprises information on the at least one buffer band.

26. A method comprising: receiving a signal from a terminal device as a direct terminal-device-to- terminal-device transmission, wherein the signal comprises information on at least one buffer band applied to the signal, the at least one buffer band comprising at least one of a lower buffer band or an upper buffer band; and decoding the signal taking into account the information on the at least one buffer band.

27. A non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: monitoring a resource pool for direct terminal-device-to-terminal-device transmissions by a plurality of terminal devices and use of buffer bands for the direct terminal-device-to-terminal device transmissions; selecting a resource for transmission from the resource pool; dimensioning at least one buffer band for the resource based on results of the monitoring for avoiding or at least reducing overlap of planned transmissions in time and frequency, wherein the at least one buffer band comprises at least one of a lower buffer band or an upper buffer band; and cause direct terminal-device-to-terminal-device transmission of a signal using the resource while applying the at least one buffer band, wherein the signal comprises information on the at least one buffer band.

28. A non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving a signal from a terminal device as a direct terminal-device-to- terminal-device transmission, wherein the signal comprises information on at least one buffer band applied to the signal, the at least one buffer band comprising at least one of a lower buffer band or an upper buffer band; and decoding the signal taking into account the information on the at least one buffer band.

29. A signal with embedded data comprising information on at least one buffer band applied to the signal, wherein the at least one buffer band comprises at least one of a lower buffer band or an upper buffer band.