Search space configuration for multicast services

Abstract

Embodiments of this disclosure relate to methods, apparatus, and computer-readable storage media for configuring search spaces for multicast services. According to embodiments of this disclosure, based on at least one of the priority of the multicast service and a corresponding type of search space set, a first device determines at least one search space set for monitoring multicast services from a set of search space sets configured to a first device. The first device monitors multicast services from the second device within at least one search space set. This solution supports monitoring multicast services in public search space sets, user-specific search space sets, or multicast search space sets in different scenarios.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to the field of communications, and more particularly, to a method, apparatus, and computer-readable medium for configuring a search space for a multicast service. Background Art

[0002] In the recent 3GPP specification Release 17 (Rel-17) for 5G New Radio (NR), it was agreed to support multicast and broadcast services. One goal is to specify a group scheduling mechanism that allows user equipment (UE) to receive multicast / broadcast services in RAN1 and RAN2. In addition, the goal includes specifying the necessary enhancements required to achieve simultaneous operation with unicast reception.

[0003] Single Cell Point-to-Multipoint (SC-PTM) is a transmission scheme that supports multicast and broadcast services. It has the benefit of reusing the control / data physical channels defined for unicast / point-to-point (PTP) transmissions, and also enables efficient multiplexing flexibility between unicast and multicast / broadcast transmissions. Rel-17 is expected to consider and specify methods for SC-PTM to support 5G NR multicast services. Summary of the invention

[0004] In general, example embodiments of the present disclosure provide methods, apparatus, and computer-readable media for search space configuration for multicast services.

[0005] In a first aspect, a method is provided. The method includes: determining, at a first device, from a set of search space sets configured to the first device, at least one search space set for monitoring multicast services from a second device based on at least one of a priority of the multicast service and a corresponding type of the search space set; and monitoring the multicast service from the second device in the at least one search space set.

[0006] In a second aspect, a method is provided. The method includes: determining, at a second device, from a set of search space sets configured to a first device, at least one search space set for sending a multicast service to the first device based on at least one of a priority of the multicast service and a corresponding type of the search space set; and sending the multicast service to the first device in the at least one search space set.

[0007] In a third aspect, a first device is provided. The first device includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, together with the at least one processor, cause the first device to: determine at least one search space set for monitoring multicast services from a second device based on at least one of a priority of the multicast service and a corresponding type of the search space set from a set of search space sets configured to the first device; and monitor the multicast services from the second device in the at least one search space set.

[0008] In a fourth aspect, a second device is provided. The second device includes at least one processor and at least one memory including computer program code. The at least one memory and the computer program code are configured to, together with the at least one processor, enable the second device to: determine at least one search space set for sending a multicast service to the first device based on at least one of a priority of the multicast service and a corresponding type of the search space set from a set of search space sets configured to the first device; and send the multicast service to the first device in the at least one search space set.

[0009] In a fifth aspect, a device is provided. The device includes: a component for determining a search space set for monitoring multicast services from another device from a set of search space sets configured to the device, based on at least one of a priority of the multicast service and a corresponding type of the search space set; and a component for monitoring the multicast service from the other device in the search space set.

[0010] In a sixth aspect, an apparatus is provided. The apparatus includes: a component for determining a search space set for sending a multicast service to another device from a set of search space sets configured to the other device, based on at least one of a priority of the multicast service and a corresponding type of the search space set; and a component for sending the multicast service to the other device in the search space set.

[0011] In a seventh aspect, a computer program product is provided, the computer program product being stored on a computer readable medium and comprising machine executable instructions. When the machine executable instructions are executed, the machine is caused to perform the method according to the first or second aspect.

[0012] In an eighth aspect, a computer-readable storage medium is provided, comprising program instructions stored thereon. When the instructions are executed by a device, the device is caused to execute the method according to the first or second aspect above.

[0013] It should be understood that the invention summary is not intended to identify the key or essential features of the embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of some example embodiments of the present disclosure in the accompanying drawings, in which:

[0015] Figure 1 An example communication network is shown in which example embodiments of the present disclosure may be implemented;

[0016] Figure 2 A schematic diagram showing interactions between devices according to some example embodiments of the present disclosure;

[0017] FIG. 3A to FIG. 3C Different scenarios for processing search space set priorities according to some example embodiments of the present disclosure are shown;

[0018] Figure 4 A flowchart illustrating an example method according to some example embodiments of the present disclosure;

[0019] Figure 5 A flowchart showing a method according to some example embodiments of the present disclosure is shown;

[0020] Figure 6 shows a simplified block diagram of an apparatus suitable for implementing an embodiment of the present disclosure; and

[0021] Figure 7 A block diagram illustrating an example computer-readable medium according to some example embodiments of the present disclosure;

[0022] Throughout the drawings, the same or similar reference numbers denote the same or similar elements. DETAILED DESCRIPTION

[0023] The principles of the present disclosure will now be described with reference to some example embodiments. It should be understood that these embodiments are described only for illustrative purposes and to help those skilled in the art understand and implement the present disclosure, without indicating any limitation to the scope of the present disclosure. The disclosure described herein can be implemented in various ways except for the way described below.

[0024] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0025] References in this disclosure to "one embodiment," "an embodiment," "an example embodiment," etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. In addition, such phrases do not necessarily refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in conjunction with an example embodiment, it is considered that whether or not explicitly described, it is within the knowledge of those skilled in the art to affect the feature, structure, or characteristic in relation to other embodiments.

[0026] It should be understood that although the terms "first" and "second" and the like may be used to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish different elements. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the exemplary embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0027] The terms used herein are used only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be further understood that the terms "comprises", "comprising", "has", "having", "includes", and / or "including", when used herein, specify the presence of the features, elements, and / or components, etc., but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0028] As used in this application, the term "circuitry" may refer to one or more or all of the following: (a) a pure hardware circuit implementation (e.g., implementation in analog and / or digital circuitry only) and (b) a combination of hardware circuitry and software, such as (as applicable):

[0029] (i) a combination of analog and / or digital hardware circuits and software / firmware, and

[0030] (ii) any portion of hardware processor(s) (including digital signal processor(s)), software and memory(s) with software that work together to enable a device (such as a mobile phone or server) to perform various functions, and (c) hardware circuit(s) and / or processor(s), such as microprocessor(s) or portion(s) of microprocessor(s), which requires software (such as firmware) to operate, but where the software is not required for operation, the software may not be present.

[0031] This definition of circuitry applies to all uses of this term in this application, including in any claims. As another example, as used in this application, the term circuitry also includes an implementation of only 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. For example, if applicable to a particular claim element, the term circuitry also covers a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular network device, or other computing or network device.

[0032] As used herein, the term "communication network" refers to a network that complies with any suitable communication standard, such as Long Term Evolution (LTE), Advanced LTE (LTE-A), Wideband Code Division Multiple Access (WCDMA), High Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), New Radio (NR), etc. In addition, the communication between the terminal device and the network device in the communication network can be carried out according to any suitable communication protocol, including but not limited to the first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, future fifth generation (5G) communication protocol, and / or any other currently known or future developed protocol. The embodiments of the present disclosure can be applied to various communication systems. In view of the rapid development of communication, there will certainly be future types of communication technologies and systems to embody the present disclosure. The scope of the present disclosure should not be considered to be limited to the above-mentioned systems.

[0033] As used herein, the term "network device" refers to a node in a communication network through which a terminal device accesses the network and receives services from the network. A network device may refer to a base station (BS) or an access point (AP), for example, a NodeB (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR NB (also known as a gNB), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), a relay, a low-power node (such as a femto, a micro), etc., depending on the terminology and technology applied. In the following description, the terms "network device", "BS" and "node" may be used interchangeably.

[0034] The term "terminal device" refers to any terminal device capable of wireless communication. By way of example and not limitation, a terminal device may also be referred to as a communication device, user equipment (UE), user station (SS), portable user station, mobile station (MS) or access terminal (AT). Terminal devices may include, but are not limited to: mobile phones, cellular phones, smart phones, voice over IP (VoIP) phones, wireless local loop phones, tablet computers, wearable terminal devices, personal digital assistants (PDAs), portable computers, desktop computers, image capture terminal devices (such as digital cameras), game terminal devices, music storage and playback devices, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop embedded devices (LEEs), laptop mounted devices (LMEs), USB software dongles, smart devices, wireless client equipment (CPEs), Internet of Things (IoT) devices, watches or other wearable devices, head mounted displays (HMDs), vehicles, drones, medical devices and applications (such as remote surgery), industrial devices and applications (such as robots and / or other wireless devices operating in industrial and / or automated processing chain environments), consumer electronic devices, devices operating on commercial and / or industrial wireless networks, and the like. In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" may be used interchangeably.

[0035] Although the functions described herein may be performed in fixed and / or wireless network nodes in various example embodiments, in other example embodiments, the functions may be implemented in a user equipment device (e.g., a mobile phone or tablet or laptop or desktop computer or mobile IOT device or fixed IOT device). For example, the user equipment device may be appropriately equipped with the corresponding capabilities described for connection to (multiple) fixed and / or wireless network nodes. The user equipment device may be a user device and / or a control device, such as a chipset or processor, configured to control the user device when installed therein. Examples of these functions include bootstrapping server functions and / or home subscriber servers, which may be implemented in a user equipment device by providing the user equipment device with software configured to cause the user equipment device to execute from the perspective of these functions / nodes.

[0036] In the recent Rel-17 work items for 5G NR in 3GPP, support for multicast and broadcast services was approved. One goal is to specify the group scheduling mechanism in RAN1 and RAN2 to allow UEs to receive multicast / broadcast services using the 5G NR air interface. In addition, the goals include specifying the necessary enhancements required to achieve synchronized operation with unicast reception. SC-PTM is one of the transmission schemes to support multicast and broadcast services. It has the benefit of reusing the control / data physical channels defined for unicast / PTP transmission, and also enables efficient multiplexing flexibility between unicast and multicast / broadcast transmissions. It is expected that Rel-17 will consider and specify the approach of SC-PTM to support 5G NR multicast services.

[0037] In NR, the physical downlink control channel (PDCCH) can be used to convey downlink control information (DCI). Orthogonal frequency division multiplexing (OFDM) waveforms and polar codes can be used. PDCCH can use one of every four resource elements for demodulation reference signaling. DCI can be used to indicate resource allocation for downlink (DL) and / or uplink (UL). It can also be used for other purposes such as carrier aggregation and bandwidth part (BWP) (de)activation, frame structure indication (group common PDCCH) and power control updates.

[0038] The monitoring of PDCCH can be performed in a blind search manner. Blind search (or blind decoding) may refer to the process by which the UE searches for its PDCCH by monitoring a set of PDCCH candidates in each monitoring opportunity. The monitoring opportunity may be once in a time slot, once in multiple time slots, or multiple times in a time slot. A blind search for PDCCH may be arranged by mapping to a parallel search space (SS) set of one or more control resource sets (CORESETs). During a PDCCH blind search, the UE may monitor predefined control channel elements (CCEs), aggregated CCEs, and / or downlink control information (DCI) formats at predefined times corresponding to the configured monitoring opportunities.

[0039] CCEs may be arranged in predefined CORESETs configured via higher layer signaling. For example, each CCE may include 6 resource element groups (REGs), each REG containing 12 subcarriers within 1 OFDM symbol, and 1, 2, or 3 REG bundles. REG bundles may be mapped to a CORESET using either interleaved mapping or non-interleaved mapping. The UE may assume that the REG bundle defines the precoder granularity in frequency and time used by a network device (such as a gNB) when transmitting a PDCCH. CORESET resources may be configured in units of 6 resource blocks in the frequency domain. In Release 15 of the 3GPP specification, the maximum number of CORESETs that can be configured for a BWP in a cell is 3 for a UE, and the maximum number of SS sets that can be configured for a BWP in a cell is 10 for a UE, respectively.

[0040] The UE is expected to monitor PDCCH candidates for up to 4 DCI formats, including up to 3 DCI formats with CRC scrambled by the cell radio network temporary identifier (C-RNTI) of each serving cell (delay sensitive), and one DCI format with CRC scrambled by the other radio network temporary identifier (RNTI) (delay insensitive).

[0041] The PDCCH candidates are mapped to CCEs using a hash function. For a search space set s associated with a control resource set (CORESET) p, the CCE index of aggregation level L can be determined based on a hash function, where the number of PDCCH candidates mapped to the SS set s of CCE aggregation level L can be fixed in the 3GPP specification or configured by a network device (such as a gNB). For a user-specific search space (USS) set, based on the initial seed Y used for randomization of the hash function P，-1 The determined hash offset changes every time slot, while for the common search space (CSS) set, the hash offset is always 0.

[0042] In Rel-15 of the 3GPP specification, the maximum number of blind decoding (BD) and channel estimation (in terms of the number of unique CCEs) that a UE can perform per timeslot is defined as a function of the subcarrier spacing. In Rel-16 of the 3GPP specification, on a primary cell (Pcell) or primary secondary cell (PScell), the gNB can configure the number of CCEs or BDs that exceeds the UE capabilities within a timeslot. In this case, the UE is allowed to discard (i.e., not monitor) the (multiple) USSs with the highest (multiple) indices until the number of CCEs or BDs meets the UE capabilities. For CSS, the gNB needs to always ensure that the PDCCH candidates and CCEs do not exceed the UE capabilities.

[0043] As mentioned above, in the 3GPP specification Rel-15 / 16, two SS types are defined, namely CSS and USS. On the one hand, the CCE index of the CSS is the same for different UEs in a cell, while the CCE index of the USS is different for different UEs in a cell. On the other hand, in the case of PDCCH overbooking, the CSS always has a higher priority than the USS, but the ultra-reliable and low-latency communication (URLLC) service can only be monitored in the USS. In addition, for carrier aggregation, only PDCCH candidates in the USS can be monitored on the secondary cell (Scell). If the multicast service traffic is always monitored in the CSS, this may have a potential impact on the URLLC service monitored in the USS in the case of PDCCH overbooking. If the multicast service traffic is always monitored in the USS, this may have a potential impact on the multicast services with higher priority (e.g., public safety for life safety alerts for tsunamis and earthquake events). Therefore, how to consider the SS design for 5G NR multicast is an important issue that needs to be addressed.

[0044] The embodiments of the present disclosure propose a solution for SS configuration of multicast services. The solution supports monitoring of multicast services in CSS, USS or new SS in different scenarios, thereby solving the above-mentioned problems and one or more other potential problems. The solution can minimize the impact on 3GPP specification Rel-15 / 16. Although the embodiments of the present disclosure are described below with reference to multicast services, it is to be understood that the embodiments of the present disclosure are also applicable to broadcast services. As used herein, the term "multicast service" refers to data scheduled by a network device for a specific user or terminal device group, and the term "broadcast service" refers to data scheduled by a network device for all users or terminal devices interested in receiving the data.

[0045] The following will refer to Figures 1 to 7 The principles and implementations of the present disclosure are described in detail. In the following, the terms "multicast service", "multicast service", "multicast service business", "broadcast service", "broadcast service" and "broadcast service business" may be used interchangeably.

[0046] Figure 1 An example communication network 100 in which the present disclosure may be implemented is shown. The communication network 100 includes network devices 120 and terminal devices 110-1, 110-2, ... 110-N, which may be collectively referred to as "(multiple) terminal devices" 110. The network 100 may provide one or more cells 102 to serve the terminal devices 110. It should be understood that the number of network devices, terminal devices, and / or cells is given for illustrative purposes and does not indicate any limitation of the present disclosure. The communication network 100 may include any suitable number of network devices, terminal devices, and / or cells suitable for implementing the present disclosure.

[0047] The communication in the communication system 100 can be implemented according to any appropriate (multiple) communication protocols, including but not limited to first generation (1G) cellular communication protocols, second generation (2G), third generation (3G), fourth generation (4G) and fifth generation (5G), as well as wireless local network communication protocols, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, etc., and / or any other currently known or future developed protocols. In addition, the communication can utilize any appropriate wireless communication technology, including but not limited to: code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplex (FDD), time division duplex (TDD), multiple input multiple output (MEMO), orthogonal frequency division multiple access (OFDMA) and / or any other currently known or future developed technology.

[0048] Figure 2 200 between devices according to some example embodiments of the present disclosure. For example, the interaction 200 involves Figure 1 The terminal device 110 and the network device 120 are shown.

[0049] like Figure 2 As shown, the network device 120 configures a group of SS sets for the terminal device 110. The network device 120 determines 220 from the group of SS sets an SS set for sending multicast services to the terminal device 110. Similarly, the terminal device 110 determines 230 from the group of SS sets an SS set for monitoring multicast services from the network device 120. Then, the network device 120 sends 240 the multicast services to the terminal device 110 in the SS set. Accordingly, the terminal device 110 monitors 240 the multicast services from the network device 120 in the SS set.

[0050] In some example embodiments, one of the configured SS sets may be a CSS set or a USS set. Multicast services with a priority higher than a threshold (e.g., services for life safety alerts for tsunamis and earthquake events) may be sent by the network device 120 in the CSS set and monitored by the terminal device 110 in the CSS set, where the DCI may be scrambled using a group radio network temporary identifier (G-RNTI). Multicast services with a priority lower than a threshold (e.g., broadcast / multicast traffic information in a connected vehicle network) may be sent / monitored in the USS set, where the DCI may be scrambled using the G-RNTI.

[0051] In some example embodiments, multicast services may be sent by network device 120 in a CSS set and monitored by terminal device 110 in the CSS set, and an initial seed for calculating a CCE index of the CSS set may be equal to 0. The index of the CSS set may be determined according to the provisions of 3GPP specification Rel-15 / 16.

[0052] In some example embodiments, multicast traffic may be sent by network device 120 in a USS set and monitored by terminal device 110 in a USS set, and the USS set may contain an offset or may be configured with a fixed offset. The offset may define an initial seed Y for the slot-based randomization of the hash function of the USS set. P，-1 For example, the initial seed Y P，-1 It can be determined based on the offset and C-RNTI allocated to the terminal device 120. Alternatively, the initial seed Y P，-1 It can be determined based only on the configured offset. Here, the offset can be configured by the network device using higher layer signaling.

[0053] In this way, different terminal devices included in the multicast group can have different offset values, which produce the same CCE index. This can provide greater flexibility for PDCCH candidate mapping for multicast. For example, different offset values ​​can be applied to different multicast services. In this way, different multicast services can be associated with the same PDCCH candidate using different mappings. In addition, if different multicast services are not intended to be transmitted / monitored simultaneously, the configured offset can cause all multicast services to be associated with the same PDCCH candidate. In addition, considering the common frequency resource issue of BWP operation, this offset configuration can ensure that the PDCCH candidates for multicast services are within the overlapping / common frequency resource area of ​​all configured BWPs.

[0054] In some example embodiments, multicast traffic may be transmitted / monitored in a USS set, and the USS set may be configured with an initial seed Y P，-1 , used to calculate the CCE index to be monitored in the USS set. The initial seed can be applied to all RNTIs to be monitored in the USS set.

[0055] Alternatively, in some example embodiments, only the configuration for the initial seed Y P，-1 The offset of the SS set or configuration has an initial seed Y P，-1 The SS set with the G-RNTI scrambled can be used to send / monitor multicast services. Other SS sets without offsets and initial seeds can only be used to send / monitor unicast services. The CCE indexes of these SS sets can be calculated based on the C-RNTI specified in the 3GPP specification Rel-15 / 16.

[0056] Alternatively, in some example embodiments, the multicast service may be sent by the network device 120 in a USS set and monitored by the terminal device 110 in the USS set, and the USS set may be configured to have no initial seed. The network device 120 may send a configuration regarding the multicast service to the terminal device 110 via dedicated radio resource control (RRC) signaling, the configuration indicating the initial seed Y. P，-1 The offset can implicitly indicate to the terminal device 110 the priority of the multicast service and whether the multicast service should be monitored in the CSS set or the USS set. For example, if the initial seed Y determined according to the configured offset value is P，-1 If the initial seed Y is determined according to the configured offset value, it can implicitly indicate that the corresponding multicast service has a high priority and should be monitored centrally in the CSS. P，-1 If it is not equal to 0, it may implicitly indicate that the corresponding multicast service has a lower priority and should therefore be monitored centrally in the USS.

[0057] In some example embodiments, in the case of PDCCH overbooking, or in the case where the number of CCEs or BDs configured by network device 120 exceeds the capabilities of terminal device 110, terminal device 110 may discard (i.e., not monitor) the USS(s) with the highest index(es) until the number of CCEs or BDs meets the UE capabilities. For CSS, network device 120 may always have to ensure that the PDCCH candidates and CCEs do not exceed the UE capabilities.

[0058] In some example embodiments, a multicast SS (MSS) set may be defined for multicast, which is different from the CSS and the USS. The MSS may have similar characteristics to the CSS. For example, the initial seed of the hash function of the MSS may be equal to 0. In some example embodiments, RRC signaling may be used by the network device 120 to configure the MSS to the terminal device 110. The RRC signaling for MSS configuration may be similar to the RRC signaling for USS configuration, except that the DCI format field may be either omitted because only DCI formats related to PDSCH scheduling are utilized, or the DCI format field may be modified by using a new field with possible enumerated values ​​to indicate whether a specific DCI format in the DCI format subset related to PDSCH scheduling is utilized.

[0059] In some example embodiments, if an MSS set is configured to terminal device 110, multicast traffic may be sent in the MSS set by network device 120 and monitored in the MSS set by terminal device 110. For example, an MSS set may not be used to send / monitor unicast traffic.

[0060] In some example embodiments, the priority of the MSS set may be determined based on the index of the MSS set. That is, the priority of the MSS may be between the priorities of the CSS and USS sets, may be lower than the priorities of all USS sets, or may be between the priorities of different USS sets. In the event of an oversubscription of the PDCCH or the number of CCEs or BDs configured by the network device 120 exceeds the capability of the terminal device 110, the terminal device 110 may discard (i.e., not monitor) the MSS or USS with the highest (multiple) indexes until the number of CCEs or BDs meets the UE capability. For the CSS, the network device 120 may always have to ensure that the PDCCH candidates and CCEs do not exceed the UE capability.

[0061] FIG. 3A to FIG. 3C Different scenarios for processing the priority of search space sets according to some example embodiments of the present disclosure are shown. FIG. 3A to FIG. 3C In the SS set, the character "s" indicates the index of the SS set, the character "k" indicates the period of the SS set, the character "o" indicates the offset of the SS set, and the character "d" indicates the duration of the SS set. That is, the values ​​of "k" and "o" identify the starting time slot of the SS set, and the value of "d" indicates the number of consecutive time slots to monitor the SS set starting from the starting time slot identified by "k" and "o". For a specific SS set, the value in the corresponding time slot indicates the number of CCEs in the time slot that need to be monitored for possible PDCCH candidates.

[0062] Figure 3A Scenario 310 is shown, in which CSS sets 311 and 312, USS sets 313 and 314, and MSS set 315 are configured. According to the indexes of SS sets 311 to 315, their priority order can be determined as: CSS set 311>CSS set 312>USS set 313>USS set 314>MSS set 315. In the case of PDCCH overbooking or the number of CCEs or BDs configured by the network device exceeds the UE capability, the CCE of MSS set 315 with index s=7 may be ignored in time slot 0 because MSS set 315 has the lowest priority relative to other SS sets.

[0063] Figure 3BScenario 320 is shown, in which CSS sets 321 and 322, MSS set 323, and USS sets 324 and 325 are configured. According to the indexes of SS sets 321-325, their priority order can be determined as: CSS set 321>CSS set 322>MSS set 323>USS set 324>USS set 325. In the case of PDCCH overbooking or the number of CCEs or BDs configured by the network device exceeds the UE capability, the CCE of USS set 325 with index s=7 may be ignored in time slot 0 because USS set 325 has the lowest priority relative to other SS sets.

[0064] Figure 3C Scenario 330 is shown, in which CSS sets 331 and 332, MSS set 334, and USS sets 333 and 335 are configured. According to the indexes of SS sets 321-325, their priority order can be determined as: CSS set 331>CSS set 332>USS set 333>MSS set 334>USS set 335. In the case of PDCCH overbooking or the number of CCEs or BDs configured by the network device exceeds the UE capability, the CCE of USS set 335 with index s=7 may be ignored in time slot 0 because USS set 335 has the lowest priority relative to other SS sets.

[0065] As can be seen from the above, if the MSS is configured to the terminal device using RRC signaling, multicast services can be sent / monitored in the MSS. In the case of PDCCH overbooking or the number of CCEs or BDs configured by the network device exceeds the UE capacity, the terminal device can consider its priority based on the index of the USS and MSS sets and discard (i.e., not monitor) the SS set.

[0066] Figure 4 A flowchart of an example method 400 according to some example embodiments of the present disclosure is shown. The method 400 may be performed at Figure 1 and / or Figure 2 The method 400 is implemented at the terminal device 110 shown. Hereinafter, the terminal device 110 is also referred to as a "first device" and the network device 120 is also referred to as a "second device". It should be understood that the method 400 may include additional blocks not shown and / or some of the blocks shown may be omitted, and the scope of the present disclosure is not limited in this respect.

[0067] At block 410, the first device determines at least one search space set for monitoring multicast traffic from a second device from a set of search space sets configured to the first device based on at least one of a priority of the multicast traffic and a corresponding type of the search space set.

[0068] At block 420, the first device monitors at least one search space set for multicast traffic from the second device.

[0069] In some example embodiments, the group search space set may include at least one common search space set and at least one user-specific search space set. Based on determining that the priority of the multicast service meets a predetermined criterion, the first device may determine at least one search space set for monitoring the multicast service from the at least one common search space set. Based on determining that the priority of the multicast service does not meet the predetermined criterion, the first device may determine at least one search space set for monitoring the multicast service from the at least one user-specific search space set.

[0070] In some example embodiments, in response to the priority of the multicast service exceeding a threshold, the first device may determine that the priority of the multicast service meets a predetermined criterion. In response to the priority of the multicast service not exceeding the threshold, the first device may determine that the priority of the multicast service does not meet the predetermined criterion.

[0071] In some example embodiments, the first device may select, from at least one user-specific search space set, a user-specific search space set configured with an offset for hash function randomization of the user-specific search space set as at least one search space set for monitoring the multicast service.

[0072] In some example embodiments, the first device may receive a configuration indicating a priority of the multicast service from the second device.

[0073] In some example embodiments, at least one search space set may be configured with an offset for hash function randomization of the at least one search space set, and the first device may determine an initial seed based at least on the offset. The first device may determine the initial seed based on the offset and the C-RNTI of the first device. The first device may determine a control channel element to be monitored in the at least one search space set based on the initial seed, and detect the determined control channel element for a multicast service from the second device.

[0074] In some example embodiments, at least one search space set may be configured with an initial seed for determining control channel elements to be monitored in the at least one search space set. The first device may determine the control channel element based on the initial seed and monitor the determined control channel element for a multicast service from the second device.

[0075] In some example embodiments, based on determining that the group search space set includes a multicast search space set, the first device may determine the multicast search space set as the at least one search space set for monitoring a multicast service.

[0076] In some example embodiments, the priority of the multicast search space set is determined based on an index of a user-specific search space set and / or a multicast search space set in the multicast search space set included in the group search space set.

[0077] In some example embodiments, the first device may determine control channel elements to be monitored in at least one search space set based on a predefined initial seed, and monitor the determined control channel elements for a multicast service from the second device.

[0078] In some example embodiments, the first device may be a terminal device, and the second device may be a network device serving the terminal device.

[0079] Figure 5 A flowchart of an example method 500 according to some example embodiments of the present disclosure is shown. The method 500 may be performed at Figure 1 and / or Figure 2 The method 500 is implemented at the network device 120 shown. Hereinafter, the terminal device 110 is also referred to as the "first device" and the network device 120 is also referred to as the "second device". It should be understood that the method 500 may include additional blocks not shown and / or some of the blocks shown may be omitted, and the scope of the present disclosure is not limited in this respect.

[0080] At block 510, the second device determines at least one search space set for sending a multicast service to the first device from a set of search space sets configured to the first device based on at least one of a priority of the multicast service and a corresponding type of the search space set.

[0081] At block 520, the second device sends multicast traffic to the first device in at least one set of search spaces.

[0082] In some example embodiments, the group search space set may include at least one common search space set and at least one user-specific search space set. Based on determining that the priority of the multicast service meets a predetermined criterion, the second device may determine at least one search space set for monitoring the multicast service from the at least one common search space set. Based on determining that the priority of the multicast service does not meet the predetermined criterion, the second device may determine at least one search space set for sending the multicast service from the at least one user-specific search space set.

[0083] In some example embodiments, in response to the priority of the multicast service exceeding a threshold, the second device may determine that the priority of the multicast service meets a predetermined criterion. In response to the priority of the multicast service not exceeding the threshold, the second device may determine that the priority of the multicast service does not meet the predetermined criterion.

[0084] In some example embodiments, the second device may select a user specific search space set configured with an offset for hash function randomization of the user specific search space set from the at least one user specific search space set as the at least one search space set for monitoring the multicast service.

[0085] In some example embodiments, the second device may send a configuration indicating a priority of the multicast service to the first device.

[0086] In some example embodiments, the second device may send a configuration indicating an offset for randomization of a hash function of at least one search space set to the first device.

[0087] In some example embodiments, the second device may send a configuration to the first device indicating an initial seed for determining control channel elements to be monitored in at least one search space set.

[0088] In some example embodiments, based on determining that the group search space set includes a multicast search space set, the second device may determine the multicast search space set as at least one search space set for transmitting a multicast service.

[0089] In some example embodiments, the priority of the multicast search space set is determined based on an index of a user-specific search space set and / or a multicast search space set in the multicast search space set included in the group search space set.

[0090] In some example embodiments, the first device may be a terminal device, and the second device may be a network device serving the terminal device.

[0091] In some example embodiments, an apparatus capable of performing method 400 may include components for performing the corresponding steps of method 400. The components may be implemented in any suitable form. For example, the components may be implemented in a circuit or a software module.

[0092] In some example embodiments, an apparatus (e.g., terminal device 110) capable of performing method 400 includes: a component for determining at least one search space set for monitoring multicast services from another apparatus based on a set of search space sets configured to the apparatus, based on at least one of a priority of the multicast service and a corresponding type of the search space set; and a component for monitoring multicast services from another apparatus in at least one search space set.

[0093] In some example embodiments, the group search space set includes at least one common search space set and at least one user-specific search space set, and the component for determining at least one search space set for monitoring the multicast service includes: a component for determining at least one search space set for monitoring the multicast service from at least one common search space set based on determining that the priority of the multicast service meets predetermined criteria; and a component for determining at least one search space set for monitoring the multicast service from at least one user-specific search space set based on determining that the priority of the multicast service does not meet predetermined criteria.

[0094] In some example embodiments, the device capable of executing method 400 further includes a component for determining that the priority of the multicast service meets a predetermined criterion in response to the priority of the multicast service exceeding a threshold value; and a component for determining that the priority of the multicast service does not meet the predetermined criterion in response to the priority of the multicast service not exceeding the threshold value.

[0095] In some example embodiments, a component for determining at least one search space set for monitoring a multicast service from at least one user-specific search space set includes: a component for selecting a user-specific search space set configured with an offset randomized by a hash function for the user-specific search space set from at least one user-specific search space set as at least one search space set for monitoring the multicast service.

[0096] In some example embodiments, an apparatus capable of performing method 400 further comprises means for receiving a configuration indicating a priority of the multicast service from another device.

[0097] In some example embodiments, at least one search space set is configured with an offset for hash function randomization of the at least one search space set, and a component for monitoring a multicast service from a second device in the at least one search space set includes: a component for determining an initial seed based at least on the offset; a component for determining a control channel element to be monitored in the at least one search space set based on the initial seed; and a component for monitoring the determined control channel element for a multicast service from another device.

[0098] In some example embodiments, the means for determining the initial seed comprises means for determining the initial seed based on an offset and a cell radio network temporary identifier of the apparatus.

[0099] In some example embodiments, at least one search space set is configured with an initial seed for determining control channel elements to be monitored in at least one search space set, and a component for monitoring multicast services from another device in at least one search space set includes: a component for determining the control channel elements based on the initial seed; and a component for monitoring the determined control channel elements for multicast services from another device.

[0100] In some example embodiments, the component for determining at least one search space set for monitoring multicast services includes: a component for determining to use the multicast search space set as the at least one search space set for monitoring multicast services based on determining that the group of search space sets includes the multicast search space set.

[0101] In some example embodiments, the priority of the multicast search space set is determined based on an index of a user-specific search space set and / or a multicast search space set in the multicast search space set included in the group search space set.

[0102] In some example embodiments, a component for monitoring multicast services from another device in at least one search space set includes: a component for determining control channel elements to be monitored in at least one search space set based on a predefined initial seed; and a component for monitoring the determined control channel elements for multicast services from another device.

[0103] In some example embodiments, the apparatus is a terminal device and the other apparatus is a network device serving the terminal device.

[0104] In some example embodiments, an apparatus capable of performing method 500 may include components for performing the corresponding steps of method 500. The components may be implemented in any suitable form. For example, the components may be implemented in a circuit or a software module.

[0105] In some example embodiments, an apparatus (e.g., network device 120) capable of performing method 500 includes: a component for determining at least one search space set for sending a multicast service to another apparatus from a set of search space sets configured to another apparatus, based on at least one of a priority of the multicast service and a corresponding type of the search space set; and a component for sending a multicast service to another apparatus in the at least one search space set.

[0106] In some example embodiments, the group search space set includes at least one common search space set and at least one user-specific search space set, and the component for determining at least one search space set for sending a multicast service includes: a component for determining at least one search space set for monitoring a multicast service from at least one common search space set based on determining that a priority of the multicast service meets predetermined criteria; and a component for determining at least one search space set for sending a multicast service from at least one user-specific search space set based on determining that a priority of the multicast service does not meet predetermined criteria.

[0107] In some example embodiments, the device capable of executing method 500 further includes: a component for determining that the priority of the multicast service meets a predetermined criterion in response to the priority of the multicast service exceeding a threshold value; and a component for determining that the priority of the multicast service does not meet the predetermined criterion in response to the priority of the multicast service not exceeding the threshold value.

[0108] In some example embodiments, a component for determining at least one search space set for sending a multicast service from at least one user-specific search space set includes: a component for selecting a user-specific search space set configured with an offset randomized by a hash function for the user-specific search space set from at least one user-specific search space set as at least one search space set for monitoring the multicast service.

[0109] In some example embodiments, an apparatus capable of performing method 500 further comprises means for sending a configuration indicating a priority of the multicast service to another apparatus.

[0110] In some example embodiments, an apparatus capable of performing method 500 further comprises means for sending a configuration indicating an offset for randomizing a hash function of at least one search space set to another apparatus.

[0111] In some example embodiments, an apparatus capable of performing method 500 further comprises means for sending a configuration indicating an initial seed to another apparatus, the initial seed being used to determine control channel elements to be monitored in at least one search space set.

[0112] In some example embodiments, the component for determining at least one search space set for transmitting a multicast service includes: a component for determining the multicast search space set as the at least one search space set for transmitting the multicast service based on determining that the group of search space sets includes the multicast search space set.

[0113] In some example embodiments, the priority of the multicast search space set is determined based on an index of a user-specific search space set and / or a multicast search space set in the multicast search space set included in the search space set group.

[0114] In some example embodiments, the further apparatus is a terminal device and the apparatus is a network device serving the terminal device.

[0115] Figure 6 6 is a simplified block diagram of a device 600 suitable for implementing an embodiment of the present disclosure. For example, the network device 120 and / or the terminal device 110 may be implemented by the device 600. As shown in the figure, the device 600 includes one or more processors 610, one or more memories 620 coupled to the processor 610, and one or more communication modules 640 coupled to the processor 610.

[0116] The communication module 640 is used for two-way communication. The communication module 640 has at least one antenna to facilitate communication. The communication interface may represent any interface necessary for communication with other network elements.

[0117] Processor 610 may be of any type suitable for the local technology network, and may include, as non-limiting examples, one or more of: a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 600 may have multiple processors, such as application specific integrated circuit chips that are time dependent on a clock that is synchronized with a main processor.

[0118] The memory 620 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 624, electrically programmable read-only memory (EPROM), flash memory, hard disk, compact disk (CD), digital video disk (DVD), and other magnetic and / or optical memories. Examples of volatile memories include, but are not limited to, random access memory (RAM) 622 and other volatile memories that do not persist over the duration of a power outage.

[0119] Computer program 630 includes computer executable instructions executed by associated processor 610. Program 630 may be stored in ROM 624. Processor 610 may perform any suitable actions and processes by loading program 630 into RAM 622.

[0120] The embodiments of the present disclosure may be implemented by a program 630 so that the device 600 may execute the reference Figures 2 to 5 Any process of the present disclosure discussed. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

[0121] In some example embodiments, the program 630 may be tangibly embodied in a computer-readable medium that may be included in the device 600 (e.g., the memory 620), or in other storage devices accessible by the device 600. The device 600 may load the program 630 from the computer-readable medium to the RAM 622 for execution. The computer-readable medium may include any type of tangible non-volatile memory, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. Figure 7 An example of a computer readable medium 700 in the form of a CD or DVD is shown. The computer readable medium has a program 630 stored thereon.

[0122] It should be understood that future networks may utilize network function virtualization (NFV), a network architecture concept that proposes virtualizing network node functions into "building blocks" or entities that can be operationally connected or linked together to provide services. A virtualized network function (VNF) may include one or more virtual machines that use standard or general-purpose servers rather than customized hardware to run computer program code. Cloud computing or data storage may also be utilized. In radio communications, this may mean that node operations are at least partially performed in a central / centralized unit CU (e.g., a server, host, or node), which is operationally coupled to a distributed unit DU (e.g., a radio head / node). Node operations may also be distributed among multiple servers, nodes, or hosts. It should also be understood that the distribution of labor between core network operations and base station operations may vary depending on the implementation.

[0123] In an embodiment, the server may generate a virtual network through which the server communicates with the distributed units. In general, virtual networking may involve the process of combining hardware and software network resources and network functions into a single, software-based management entity, namely a virtual network. Such a virtual network may provide flexible allocation of operations between servers and radio heads / nodes. In practice, any digital signal processing task may be performed in either the CU or the DU, and the boundary of responsibility transfer between the CU and the DU may be selected based on the implementation.

[0124] Thus, in an embodiment, a CU-DU architecture is implemented. In this case, the device 600 may be included in a central unit (e.g., a control unit, an edge cloud server, a server), which is operatively coupled (e.g., via a wireless or wired network) to a distributed unit (e.g., a remote radio head / node). That is, the central unit (e.g., an edge cloud server) and the distributed units may be independent devices that communicate with each other via a radio path or via a wired connection. Alternatively, they may communicate via a wired connection in the same entity, and so on. The edge cloud or edge cloud server may serve multiple distributed units or radio access networks. In an embodiment, at least some of the processes described may be performed by a central unit. In another embodiment, the device 600 may be instead included in a distributed unit, and at least some of the processes described may be performed by the distributed unit.

[0125] In an embodiment, the execution of at least some functions of the device 600 can be shared between two physically separate devices (DU and CU) that form an operating entity. Therefore, the device can be regarded as describing an operating entity comprising one or more physically separate devices for performing at least some of the described processes. In one embodiment, such a CU-DU architecture can provide a flexible allocation of operations between the CU and the DU. In practice, any digital signal processing task can be performed in the CU or the DU, and the boundary of the transfer of responsibilities between the CU and the DU can be selected according to the implementation. In an embodiment, the device 600 controls the execution of the process regardless of the location of the device and where the process / function is executed.

[0126] In general, various embodiments of the present disclosure may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software, which may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure are illustrated and described in block diagrams, flow charts, or using some other graphical representations, it should be understood that the boxes, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or controllers or other computing devices, or some combination thereof, as non-limiting examples.

[0127] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer executable instructions, such as instructions contained in a program module, which are executed in a device in a target real or virtual processor to perform the above-mentioned reference Figure 4 The method 400 described and / or referenced above Figure 5Method 500 described. Typically, program modules include paths, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. In various embodiments, the functions of program modules can be combined or separated between program modules as needed. The machine executable instructions of program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in local and remote storage media.

[0128] The program code for executing the method of the present disclosure can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device so that the program code, when executed by the processor or controller, the function / operation specifically described in the flow chart and / or block diagram is realized. The program code can be executed completely on the machine, partially on the machine, as an independent software package, partially on the machine and partially on a remote machine, or completely on a remote machine or server.

[0129] In the context of the present disclosure, computer program codes or related data may be carried by any suitable carrier to enable a device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include signals, computer readable media, etc.

[0130] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or equipment, or any suitable combination thereof. More specific examples of computer readable storage media include an electrical connection with one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof.

[0131] In addition, although the operations are described in a particular order, this should not be construed as requiring the specific order shown or to be performed in order, or all the operations shown, to obtain the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, although the above discussion includes several specific implementation details, these should not be interpreted as limitations on the scope of the present disclosure, but should be interpreted as specific descriptions of the features of a particular embodiment. Certain features described in the context of a separate embodiment may also be implemented in combination in a single embodiment. Conversely, the various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination.

[0132] Although the disclosure is described in language specific to structural features and / or methodological acts, it should be understood that the disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A device for communication, comprising: means for determining, from a set of search space sets configured to the device, at least one search space set for monitoring multicast traffic from another device based on a priority of the multicast traffic and a corresponding type of the search space sets, wherein the set of search space sets includes at least one common search space set and at least one user-specific search space set; as well as Means for monitoring the multicast service from the additional device in one or more common search space sets based on determining the at least one search space set for monitoring the multicast service from the at least one common search space set.

2. The apparatus according to claim 1, further comprising: Means for monitoring the multicast service from the additional device in one or more user-specific search space sets based on determining the at least one search space set for monitoring the multicast service from the at least one user-specific search space set.

3. The apparatus according to claim 1 or 2, wherein the means for determining the at least one search space set for monitoring the multicast service comprises: means for determining, from the at least one common search space set, the at least one search space set for monitoring the multicast service based on determining that the priority of the multicast service satisfies a predetermined criterion; as well as means for determining the at least one search space set for monitoring the multicast service from the at least one user-specific search space set based on determining that the priority of the multicast service does not satisfy the predetermined criterion.

4. The apparatus according to claim 3, further comprising: means for determining, in response to the priority of the multicast service exceeding a threshold, that the priority of the multicast service satisfies the predetermined criterion; as well as Means for determining that the priority of the multicast service does not satisfy the predetermined criterion in response to the priority of the multicast service not exceeding the threshold.

5. The apparatus of claim 3, wherein the means for determining the at least one search space set for monitoring the multicast service from the at least one user-specific search space set comprises: means for selecting, from the at least one user-specific search space set, the user-specific search space set configured with an offset for hash function randomization of the user-specific search space set as the at least one search space set for monitoring the multicast service.

6. The apparatus according to claim 3, further comprising: Means for receiving, from said further apparatus, a configuration indicative of said priority of said multicast service.

7. The apparatus of claim 3, wherein the at least one search space set is configured with an offset for randomizing a hash function of the at least one search space set, and the means for monitoring the multicast service from the further apparatus in the at least one search space set comprises: means for determining an initial seed based at least on the offset; means for determining control channel elements to be monitored in said at least one search space set based on said initial seed; as well as Means for monitoring the determined control channel element for the multicast service from the further device.

8. The apparatus of claim 7, wherein the means for determining the initial seed comprises: Means for determining the initial seed based on the offset and a cell radio network temporary identifier of the apparatus.

9. The apparatus of claim 3, wherein the at least one search space set is configured with an initial seed, the means for determining control channel elements to be monitored in the at least one search space set, and the means for monitoring the multicast service from the further apparatus in the at least one search space set comprises: means for determining said control channel element based on said initial seed; as well as Means for monitoring the determined control channel element for the multicast service from the further device.

10. The apparatus according to claim 1 or 2, wherein the means for determining the at least one search space set for monitoring the multicast service comprises: The method is configured to determine the multicast search space set as the at least one search space set for monitoring the multicast service based on determining that the group of search space sets includes a multicast search space set.

11. The apparatus according to claim 10, wherein the priority of the multicast search space set is determined based on an index of a user-specific search space set and / or a multicast search space set included in the group of search space sets.

12. The apparatus of claim 10, wherein the means for monitoring the multicast traffic from the other apparatus in the at least one search space set comprises: means for determining control channel elements to be monitored in the at least one search space set based on a predefined initial seed; as well as Means for monitoring the determined control channel element for the multicast service from the further device.

13. The apparatus according to any one of claims 1 to 12, wherein the apparatus is a terminal device, and the further apparatus is a network device serving the terminal device.

14. An apparatus for communication, comprising: means for determining, from a set of search space sets configured to further devices, at least one search space set for transmitting the multicast service to the further devices based on a priority of the multicast service and a corresponding type of the search space sets, wherein the set of search space sets comprises at least one common search space set and at least one user-specific search space set; as well as Means for transmitting the multicast service to the additional apparatus in one or more common search space sets based on determining the at least one search space set for transmitting the multicast service from the at least one common search space set.

15. The apparatus according to claim 14, further comprising: Means for transmitting the multicast service to the additional apparatus in one or more user-specific search space sets based on determining the at least one search space set for transmitting the multicast service from the at least one user-specific search space set.

16. The apparatus according to claim 14 or 15, wherein the means for determining the at least one search space set for sending the multicast service comprises: means for determining, from the at least one common search space set, the at least one search space set for sending the multicast service based on determining that the priority of the multicast service satisfies a predetermined criterion; as well as means for determining the at least one search space set for transmitting the multicast service from the at least one user-specific search space set based on determining that the priority of the multicast service does not satisfy the predetermined criterion.

17. The apparatus according to claim 16, further comprising: means for determining, in response to the priority of the multicast service exceeding a threshold, that the priority of the multicast service satisfies the predetermined criterion; as well as means for determining, in response to the priority of the multicast service not exceeding the threshold, that the priority of the multicast service does not satisfy the predetermined criterion.

18. The apparatus of claim 16, wherein the means for determining the at least one search space set for transmitting the multicast service from the at least one user-specific search space set comprises: A means for selecting, from the at least one user-specific search space set, the user-specific search space set configured with an offset for hash function randomization of the user-specific search space set as the at least one search space set for transmitting the multicast service.

19. The apparatus according to claim 16, further comprising: Means for sending a configuration indicating the priority of the multicast service to the further device.

20. The apparatus according to claim 14 or 15, further comprising: Means for sending to the further apparatus a configuration indicating an offset for hash function randomization of the at least one search space set.

21. The apparatus according to claim 14 or 15, further comprising: Means for sending a configuration indicating an initial seed to the further apparatus, the initial seed being used to determine control channel elements to be monitored in the at least one set of search spaces.

22. The apparatus according to claim 14 or 15, wherein the means for determining the at least one search space set for sending the multicast service comprises: The method is configured to determine, based on determining that the group of search space sets includes a multicast search space set, the multicast search space set as the at least one search space set for sending the multicast service.

23. The apparatus according to claim 22, wherein the priority of the multicast search space set is determined based on an index of a user-specific search space set and / or the multicast search space set in the group of search space sets.

24. The apparatus according to any one of claims 14 to 23, wherein the further apparatus is a terminal device, and the apparatus is a network device serving the terminal device.

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