WO2018059683A1

WO2018059683A1 - Network node, client device and methods thereof

Info

Publication number: WO2018059683A1
Application number: PCT/EP2016/073193
Authority: WO
Inventors: Neng Wang; Chaitanya TUMULA; Sergei SEMANOV; Alberto-Jimenez FELTSTROM; Zuleita HO; Junshi Chen
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2016-09-29
Filing date: 2016-09-29
Publication date: 2018-04-05
Also published as: CN110393031A; CN110393031B

Abstract

The invention relates to a network node and client device. The network node (100) comprises processor (102) configured to classify one or more applications associated with one or more client devices (300a, 300b,…, 300n) into one or more service classes, wherein each service class corresponds to a Quality of Service, QoS, requirement, group applications in a service class into one or more transmission units for the service class, map the one or more transmission units for the service class onto one or more physical resource units based on at least one of the QoS requirement for the service class and a channel quality information associated with the one or more client devices (300a, 300b,…, 300n), wherein the one or more physical resource units are assigned for grant-free transmissions from the one or more client devices (300a, 300b,…, 300n) to the network node (100), a transceiver (104) configured to signal a mapping information (MI) to the one or more client devices (300a, 300b,…, 300n), wherein the mapping information (MI) comprises the mapping of the one or more transmission units for the service class onto the one or more physical resource units. The client device (300) comprises a processor (302) configured to run one or more applications, wherein each application is associated with a QoS requirement, a transceiver (304) configured to receive a mapping information (MI) from a network node (100), wherein the mapping information (MI) comprises a mapping of one or more transmission units onto one or more physical resource units for grant-free transmission, transmit data to the network node (100) in the one or more physical resource units based on the mapping information (MI), wherein the data is associated with the one or more applications. Furthermore, the invention also relates to corresponding methods, a computer program, and a computer program product.

Description

NETWORK NODE, CLIENT DEVICE AND METHODS THEREOF

Technical Field

The invention relates to a network node and a client device. Furthermore, the invention also relates to corresponding methods, a computer program, and a computer program product.

Background

Typical uplink (UL) transmission in wireless communication systems is based on scheduling grant, i.e. a user sends a UL scheduling request to a base station and the base station responds by sending back a UL grant to the user for resource allocation. With the exploding of vertical market applications, e.g. massive Machine Type Communications (mMTC) and Ultra Reliable Low-Latency Communications (URLLC), such scheduling grant-based mechanism tends to become less efficient in terms of signalling overhead and/or latency. Grant-free UL transmission, by removing scheduling request and grant procedure, has the potential of reducing both signalling overhead and latency. Meanwhile, grant-free UL transmission also introduces contention among users, which could degrade overall system performance if not dealt with properly. Resource management to improve system performance by mitigating collision, and keep implementation complexity reasonable would be critical in realistic deployment.

Besides resource allocation, inter-cell coordination could also improve system performance. In long term evolution (LTE) the following control signalling is introduced for inter-cell interference coordination:

• Relative Narrowband Transmit Power (RNTP) is sent to neighbouring eNBs, which contains 1 bit per physical resource block (PRB) in the downlink, indicating if the transmission power on that PRB will be greater than a given threshold; neighbouring eNBs can anticipate which bands would suffer more severe interference and take the right scheduling decisions immediately rather than relying on the channel quality indicator (CQI) reports of the user equipment (UE) only.

· Overload Indicator (Ol) which is triggered when high interference in the uplink direction is detected by an eNB; and will be sent to neighbouring eNBs whose UEs are potentially the source of this high interference. The Ol message contains an interference level indication of low, medium or high per PRB.

• High Interference Indicator (HII) for uplink transmissions works similarly to the previous RNTP message for the downlink. There is one bit per PRB indicating if neighbouring eNBs should expect high interference power in the near future. Hence, typically only PRBs assigned to cell-edge UEs are indicated. Reference Signal Received Power (RSRP) measurements as part of handover measurement reports can be used to identify cell edge UEs.

In a conventional solution, some high-level solutions of resource allocation for contention- based UL transmission has been proposed, including definition of Contention Transmission Unit (CTU), mapping/re-mapping between user and CTU, collision and its handling, etc. The conventional solutions for resource allocation were at high-level, and some implementation details are needed for deployment, e.g. resource management including physical resource mapping and scheduling, retransmission handling, and blind detection and decoding complexity reduction, etc. Prior inter-cell interference coordination (ICIC) solutions in LTE mainly address inter-cell interference management, not applicable to resource management in grant-free UL transmission.

Summary

An objective of embodiments of the invention is to provide a solution which mitigates or solves the drawbacks and problems of conventional solutions.

Another objective of embodiments of the invention is to provide a solution which provides improved resource management for grant-free transmissions from client devices to network nodes.

An "or" in this description and the corresponding claims is to be understood as a mathematical OR which covers "and" and "or", and is not to be understand as an XOR (exclusive OR). The above and further objectives are solved by the subject matter of the independent claims. Further advantageous implementation forms of the invention can be found in the dependent claims.

According to a first aspect of the invention, the above mentioned and other objectives are achieved with a network node for a wireless communication system, the network node comprising

a processor configured to

classify one or more applications associated with one or more client devices into one or more service classes, wherein each service class corresponds to a Quality of Service, QoS, requirement,

group applications in a service class into one or more transmission units for the service class, map the one or more transmission units for the service class onto one or more physical resource units based on at least one of the QoS requirement for the service class and a channel quality information associated with the one or more client devices, wherein the one or more physical resource units are assigned for grant-free transmissions from the one or more client devices to the network node,

a transceiver configured to

signal a mapping information to the one or more client devices, wherein the mapping information comprises the mapping of the one or more transmission units for the service class onto the one or more physical resource units.

The mapping for a service class is based on the QoS requirement for the service class, the channel quality information associated with the one or more client devices, or a combination thereof. An application in this disclosure may mean an entity that requests data transmission services. The application may e.g. be software installed or running in a client device.

A service class in this disclosure may mean a category of services with specific QoS requirements, e.g. coverage, latency, bandwidth, etc.

The network node according to the first aspect provides a number of advantages over convention solutions. The presented grouping of applications into service classes and mapping of transmission units onto physical resource units improve system performance, e.g. the grouping enables an efficient channel use. The mapping further enables efficient intra-/inter- cell coordination between network nodes in the wireless communication system. Further, semi- static scheduling can be enabled by the network node according to the first aspect so as to improve spectrum efficiency.

In a first possible implementation form of a network node according to the first aspect, the processor is configured to

assign a temporary transmission unit identity for each client device of the one or more client devices,

wherein the transceiver is configured to

signal an identity information to the one or more client devices, wherein the identity information comprises the temporary transmission unit identity. The first implementation form of using a temporary transmission unit identity for each client device facilitate search space management to reduce blind decoding complexity by the network node. In a second possible implementation form of a network node according to the first implementation form of the first aspect, the transceiver is configured to

receive grant-free transmissions from the one or more client devices in the mapped one or more physical resource units, wherein the grant-free transmissions comprises one or more temporary transmission unit identities,

wherein the processor is configured to

determine an active set of client devices among the one or more client devices based on the one or more temporary transmission unit identities,

decode the grant-free transmissions from the active set of client devices. The second implementation form of determining an active set of client devices based on temporary transmission unit identities means reduced blind decoding complexity since the search space may be limited.

In a third possible implementation form of a network node according to the second implementation form of the first aspect, the processor is configured to

re-map the one or more transmission units onto the one or more physical resource units if a number of data decoding failures corresponding to the active set of client devices exceeds a data decoding failure threshold value,

wherein the transceiver is configured to

signal an updated mapping information to the one or more client devices, wherein the updated mapping information comprises the re-mapping of the one or more transmission units onto the one or more physical resource units.

Decoding failures in this disclosure may mean that data is not successfully decoded by the network node, e.g. a data packet error. The data decoding failure threshold value may be set to different suitable failure rates.

The third implementation form of re-mapping of (logical) transmission units (TU) to (physical) resource units (RU) and signalling the re-mapping improves service quality and efficiency of channel use since the mapping can be adjusted to traffic and/or channel radio conditions. In a fourth possible implementation form of a network node according to any of the preceding implementation forms of the first aspect or to the first aspect as such, the transceiver is configured to

receive one or more reference signals from the one or more client devices,

wherein the processor is configured to

determine the channel quality information and a modulation and coding rate associated with the one or more client devices based on the received one or more reference signals, signal a modulation and coding rate information to the one or more client devices, wherein the modulation and coding rate information comprises the modulation and coding rate.

The fourth implementation form provides a mechanism for rate control thereby providing means for improving system spectrum efficiency.

In a fifth possible implementation form of a network node according to any of the preceding implementation forms of the first aspect or to the first aspect as such, the processor is configured to

obtain a first set of measurements, wherein the first set of measurements comprises one or more measured values associated with at least one of the one or more resource units, the one or more client devices, and the service class,

re-map the one or more transmission units onto the one or more physical resource units based on the first set of measurements,

wherein the transceiver is configured to

Measured values in the first set of measurements may in this disclosure relate to interference level, e.g. Interference over Thermal (loT) and/or collision, e.g. decoding failure probability, etc.

The fifth implementation form provides a signalling mechanism for enabling the sharing of updated mapping information for improved performance, such as reduced collision and increased capacity. In a sixth possible implementation form of a network node according to any of the preceding implementation forms of the first aspect or to the first aspect as such, the processor is configured to map the one or more transmission units onto the one or more physical resource units according to frequency division multiplexing, time division multiplexing, or a combination of frequency division multiplexing and time division multiplexing. The sixth implementation form of using any of the stated multiplexing mechanisms supports diversified use cases to be carried over physical channels. Frequency division multiplexing results in frequency diversity, time division multiplexing results in time diversity, and the combination results in frequency and time diversity. In a seventh possible implementation form of a network node according to any of the preceding implementation forms of the first aspect or to the first aspect as such, wherein the transceiver is configured to

signal at least one of the mapping information, the updated mapping information, the identity information, and the modulation and coding rate information to the one or more client devices via at least one of radio resource control (RRC), a medium access control (MAC) control element (CE), system information block (SIB), and physical layer signalling (such as L1 ).

The seventh implementation form provides a signalling mechanism for enabling resource management by the network node.

In an eight possible implementation form of a network node according to any of the preceding implementation forms of the first aspect or to the first aspect as such, the transceiver is configured to

signal at least one of the mapping information, the updated mapping information, the identity information, and the modulation and coding rate information to one or more other network nodes, e.g. via a backhaul interface.

The eight implementation form of providing a (backhaul) signalling mechanism for relevant information exchange enables inter-cell interference coordination and mitigation between the network nodes in the wireless communication system.

In a ninth possible implementation form of a network node according to the eight implementation form of the first aspect, the processor is configured to

obtain a second set of measurements for one or more client devices served by the one or more other network nodes, wherein the second set of measurements comprises one or more measured values associated with at least one of the one or more resource units, the one or more client devices, and the service class,

wherein the transceiver is configured to

signal a resource unit overloading indicator to the one or more other network nodes if a measured value of the second set of measurements exceeds a measurement threshold value.

The ninth implementation form of using overloading indicator based interference mitigation control improves network efficiency by enabling load balancing among (neighbouring) network nodes to avoid collision in heavily loaded RUs.

In a tenth possible implementation form of a network node according to the eighth or ninth implementation form of the first aspect, the transceiver is configured to

signal a resource unit high interference indicator to the one or more other network nodes based on at least one of the mapping information, the updated mapping information, the identity information, and the modulation and coding rate information.

The tenth implementation form of using high interference indicator based interference mitigation control improves network efficiency by enabling load balancing among (neighbouring) network nodes to avoid collision in heavily loaded RUs.

According to a second aspect of the invention, the above mentioned and other objectives are achieved with a client device for a wireless communication system, the client device comprising a processor configured to

run one or more applications, wherein each application is associated with a QoS requirement,

a transceiver configured to

receive a mapping information from a network node, wherein the mapping information comprises a mapping of one or more transmission units onto one or more physical resource units for grant-free transmission,

transmit data to the network node in the one or more physical resource units based on the mapping information, wherein the data is associated with the one or more applications.

The grant-free transmission may comprise that the client device autonomously transmits data to the network node without conventional scheduling request and grant procedure to reduce signalling overhead and potential latency in the transmission procedure. The client device according to the first aspect provides a number of advantages over convention solutions. Receiving the mapping information and transmitting data in a grant-free manner according to the mapping information improves system capacity and reduces operational complexity. Further, semi-static scheduling is also enabled so as to improve spectrum efficiency.

In a first possible implementation form of a client device according to the second aspect, the transceiver is configured to

receive an identity information from the network node, wherein the identity information comprises a temporary transmission unit identity for the client device,

include the temporary transmission unit identity in the data transmitted to the network node in the one or more physical resource units for grant-free transmission.

The first implementation form of using a temporary transmission unit identity for each client device facilitate search space management to reduce blind decoding complexity by the network node.

In a second possible implementation form of a client device according to the first implementation form of the second aspect or to the second aspect as such, the transceiver is configured to

receive an updated mapping information from the network node, wherein the updated mapping information comprises re-mapping of the one or more transmission units onto the one or more physical resource units for grant-free transmission,

retransmit the data in the one or more physical resource units based on the updated mapping information.

The second implementation form of receiving updated mapping information improves service quality and efficiency of channel use since the mapping can be adjusted to traffic and/or channel conditions.

According to a third aspect of the invention, the above mentioned and other objectives are achieved with a method for a network node, the method comprising:

classifying one or more applications associated with one or more client devices into one or more service classes, wherein each service class corresponds to a Quality of Service, QoS, requirement,

grouping applications in a service class into one or more transmission units for the service class, mapping the one or more transmission units for the service class onto one or more physical resource units based on at least one of the QoS requirement for the service class and a channel quality information associated with the one or more client devices, wherein the one or more physical resource units are assigned for grant-free transmissions from the one or more client devices to the network node,

signalling a mapping information to the one or more client devices, wherein the mapping information comprises the mapping of the one or more transmission units for the service class onto the one or more physical resource units. In a first possible implementation form of a method according to the third aspect, the method comprising

assigning a temporary transmission unit identity for each client device of the one or more client devices,

wherein the transceiver is configured to

signalling an identity information to the one or more client devices, wherein the identity information comprises the temporary transmission unit identity.

In a second possible implementation form of a method according to the first implementation form of the third aspect, the method comprising

receiving grant-free transmissions from the one or more client devices in the mapped one or more physical resource units, wherein the grant-free transmissions comprises one or more temporary transmission unit identities,

determining an active set of client devices among the one or more client devices based on the one or more temporary transmission unit identities,

decoding the grant-free transmissions from the active set of client devices.

In a third possible implementation form of a method according to the second implementation form of the third aspect, the method comprising

re-mapping the one or more transmission units onto the one or more physical resource units if a number of data decoding failures corresponding to the active set of client devices exceeds a data decoding failure threshold value,

signalling an updated mapping information to the one or more client devices, wherein the updated mapping information comprises the re-mapping of the one or more transmission units onto the one or more physical resource units. In a fourth possible implementation form of a method according to any of the preceding implementation forms of the third aspect or to the third aspect as such, the method comprising receiving one or more reference signals from the one or more client devices, determining the channel quality information and a modulation and coding rate associated with the one or more client devices based on the received one or more reference signals, signalling a modulation and coding rate information to the one or more client devices, wherein the modulation and coding rate information comprises the modulation and coding rate.

In a fifth possible implementation form of a method according to any of the preceding implementation forms of the third aspect or to the third aspect as such, the method comprising obtaining a first set of measurements, wherein the first set of measurements comprises one or more measured values associated with at least one of the one or more resource units, the one or more client devices, and the service class,

re-mapping the one or more transmission units onto the one or more physical resource units based on the first set of measurements,

signalling an updated mapping information to the one or more client devices, wherein the updated mapping information comprises the re-mapping of the one or more transmission units onto the one or more physical resource units. In a sixth possible implementation form of a method according to any of the preceding implementation forms of the third aspect or to the third aspect as such, the method comprising mapping the one or more transmission units onto the one or more physical resource units according to frequency division multiplexing, time division multiplexing, or a combination of frequency division multiplexing and time division multiplexing.

In a seventh possible implementation form of a method according to any of the preceding implementation forms of the third aspect or to the third aspect as such, the method comprising signalling at least one of the mapping information, the updated mapping information, the identity information, and the modulation and coding rate information to the one or more client devices via at least one of radio resource control (RRC), a medium access control (MAC) control element, system information block (SIB), and physical layer signalling.

In an eight possible implementation form of a method according to any of the preceding implementation forms of the third aspect or to the third aspect as such, the method comprising signalling at least one of the mapping information, the updated mapping information, the identity information, and the modulation and coding rate information to one or more other network nodes, e.g. via a backhaul interface. In a ninth possible implementation form of a method according to the eight implementation form of the third aspect, the method comprising

signalling a resource unit overloading indicator to the one or more other network nodes if a measured value of the second set of measurements exceeds a measurement threshold value.

In a tenth possible implementation form of a method according to the eighth or ninth implementation form of the third aspect, the method comprising

signalling a resource unit high interference indicator to the one or more other network nodes based on at least one of the mapping information, the updated mapping information, the identity information, and the modulation and coding rate information.

According to a fourth aspect of the invention, the above mentioned and other objectives are achieved with a method for a client device, the method comprising:

running one or more applications, wherein each application is associated with a QoS requirement,

receiving a mapping information from a network node, wherein the mapping information comprises a mapping of one or more transmission units onto one or more physical resource units for grant-free transmission,

transmitting data to the network node in the one or more physical resource units based on the mapping information, wherein the data is associated with the one or more applications.

In a first possible implementation form of a method according to the fourth aspect, the method comprising

receiving an identity information from the network node, wherein the identity information comprises temporary transmission unit identity for the client device,

including the temporary transmission unity identity in the data transmitted to the network node in the one or more physical resource units for grant-free transmission. In a second possible implementation form of a method according to the first implementation form of the fourth aspect or to the fourth aspect as such, the method comprising receiving an updated mapping information from the network node, wherein the updated mapping information comprises re-mapping of the one or more transmission units onto the one or more physical resource units for grant-free transmission,

retransmitting the data in the one or more physical resource units based on the updated mapping information.

The advantages of any method according to the third aspect or the fourth aspect, respectively, are the same as those for the corresponding device claims according to the first and second aspects, respectively.

The invention also relates to a computer program, characterized in code means, which when run by processing means causes said processing means to execute any method according to the present invention. Further, the invention also relates to a computer program product comprising a computer readable medium and said mentioned computer program, wherein said computer program is included in the computer readable medium, and comprises of one or more from the group: ROM (Read-Only Memory), PROM (Programmable ROM), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically EPROM) and hard disk drive.

Further applications and advantages of the present invention will be apparent from the following detailed description.

Brief Description of the Drawings

The appended drawings are intended to clarify and explain different embodiments of the present invention, in which:

- Fig. 1 shows a network node according to an embodiment of the invention.

- Fig. 2 shows a method according to an embodiment of the invention.

- Fig. 3 shows a client device according to an embodiment of the invention

- Fig. 4 shows a method according to an embodiment of the invention.

- Fig. 5 shows a wireless communication system according to an embodiment of the invention.

- Fig. 6 illustrates classification of applications and the mapping of TU onto physical RUs based on the classification of applications.

- Figs. 7 to 9 show time diversity mapping, frequency diversity mapping, and a combination of time and frequency diversity mapping, respectively.

- Fig. 10 shows a wireless communication system according to an embodiment of the invention. Detailed Description

Fig. 1 shows a network node 100 according to an embodiment of the invention. The network node 100 comprises a processor 102 coupled to a transceiver 104. The processor 102 and the transceiver 104 are coupled to each other by means of optional communication means 108 known in the art as illustrated in Fig. 1 with the dashed arrow. The network node 100 further comprises an optional antenna 106 coupled to the transceiver 104, which means that the network node 100 is configured for wireless communications in a wireless communication system. The processor 102 of the network node 100 is configured to classify one or more applications associated with one or more client devices 300a, 300b,..., 300n (shown in Fig. 5) into one or more service classes. Each service class corresponds to a Quality of Service (QoS) requirement, such as latency, coverage, bandwidth, etc. The processor 102 is further configured to group the applications in a service class into one or more transmission units (TUs) for the service class. The processor 102 is further configured to map the one or more TUs for the service class onto one or more physical resource units (RUs) based on at least one of the QoS requirement for the service class and a channel quality information (CQI) associated with the one or more client devices 300a, 300b,..., 300n. The physical RUs are assigned for grant-free transmissions from the one or more client devices 300a, 300b, ... , 300n to the network node 100. The transceiver 104 of the network node 100 is configured to signal a mapping information Ml to the client devices 300a, 300b,..., 300n. The mapping information Ml comprises the mapping of the one or more TUs for the service class onto the physical RUs.

Fig. 2 shows a flow chart of a corresponding method 200 which may be executed in a network node 100, such as the one shown in Fig. 1 . The method 200 comprises classifying 202 one or more applications associated with one or more client devices 300a, 300b,..., 300n into one or more service classes. Each service class corresponds to a QoS requirement as previously mentioned. The method 200 further comprises grouping 204 applications in a service class into one or more TUs for the service class. The method 200 further comprises mapping 206 the one or more TUs for the service class onto one or more physical RUs based on at least one of the QoS requirement for the service class and a CQI associated with the one or more client devices 300a, 300b,..., 300n. The physical RUs are assigned for grant-free transmissions from the one or more client devices 300a, 300b,..., 300n to the network node 100. The method 200 further comprises signalling 208 a mapping information Ml to the client devices 300a, 300b,..., 300n. The mapping information Ml comprises the mapping of the one or more TUs for the service class onto the physical RUs. The network node 100 herein may also be denoted as a radio network node, an access network node, an access point, or a base station, e.g. a Radio Base Station (RBS), which in some networks may be referred to as transmitter, "eNB", "eNodeB", "NodeB" or "B node", depending on the technology and terminology used. The radio network nodes may be of different classes such as e.g. macro eNodeB, home eNodeB or pico base station, based on transmission power and thereby also cell size. The radio network node can be a Station (STA), which is any device that contains an IEEE 802.1 1 -conformant Media Access Control (MAC) and Physical Layer (PHY) interface to the Wireless Medium (WM). The network node may also be a base station corresponding to the fifth generation (5G) wireless systems.

Fig. 3 shows a client device 300 according to an embodiment of the invention. The client device 300 comprises a processor 302 coupled to a transceiver 304. The processor 302 and the transceiver 304 are coupled to each other by means of optional communication means 308 known in the art as illustrated in Fig. 3. The client device 300 further comprises an optional antenna 306 coupled to the transceiver 304 which means that the client device 300 is configured for wireless communication in a wireless communication system.

The processor 302 of the client device 300 is configured to run one or more applications, and each application is associated with a QoS requirement. The transceiver 304 of the client device 300 is configured to receive a mapping information Ml from a network node 100. The mapping information Ml comprises a mapping of one or more TUs onto one or more physical RUs for grant-free transmission. The transceiver 304 is further configured to transmit data to the network node 100 in the one or more physical RUs based on the mapping information Ml, wherein the data is associated with the one or more applications. The data may be UL uplink data, such as for example utility metering data. The data may be associated with different applications (and corresponding services) running or being installed in the client device 300.

Fig. 4 shows a flow chart of a corresponding method 400 which may be executed in a client device 300, such as the one shown in Fig. 3. The method 400 comprises running 402 one or more applications, wherein each application is associated with a QoS requirement. The method 400 further comprises receiving 404 a mapping information Ml from a network node 100, and the mapping information Ml comprises a mapping of one or more TUs onto one or more physical RUs for grant-free transmission. The method 400 further comprises transmitting 406 data to the network node 100 in the one or more physical RUs based on the mapping information Ml, wherein data is associated with the one or more applications. The client device 300 herein may be denoted as a user device, a User Equipment (UE), a mobile station, an internet of things (loT) device, a sensor device, a wireless terminal and/or a mobile terminal, is enabled to communicate wirelessly in a wireless communication system, sometimes also referred to as a cellular radio system. The UEs may further be referred to as mobile telephones, cellular telephones, computer tablets or laptops with wireless capability. The UEs in the present context may be, for example, portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and/or data, via the radio access network, with another entity, such as another receiver or a server. The UE can be a Station (STA), which is any device that contains an IEEE 802.1 1 - conformant Media Access Control (MAC) and Physical Layer (PHY) interface to the Wireless Medium (WM). The client device 100 may also be configured for communication in 3GPP related LTE and LTE-Advanced, in WiMAX and its evolution, and in fifth generation wireless technologies, such as New Radio. Fig. 5 illustrates a wireless communication system 500 according to an embodiment of the invention. The wireless communication system 500 comprises a network node 100 and a plurality of client devices 300a, 300b,..., 300n according to embodiments of the invention. The network node 100 signals the previously described mapping information Ml to the client devices 300a, 300b,..., 300n which in turn are served by the network node 100.

The network node 100 may assign a temporary transmission unit identity to each client device of the client devices 300a, 300b,..., 300n. These temporary transmission unit identities are signalled to the client devices 300a, 300b,..., 300n in identity information IDI as illustrated in Fig. 5.

The client devices 300a, 300b,..., 300n are configured to perform grant-free transmissions to the network node 100 in the mapped physical RU, and the grant-free transmissions comprises the temporary transmission unit identity. After receiving mentioned grant-free transmissions the network node 100 determines an active set of client devices among the client devices 300a, 300b,..., 300n based on the one or more temporary transmission unit identities in the grant- free transmissions. The active set may comprises all of the client devices 300a, 300b,..., 300n or just a limited number of the client devices 300a, 300b,..., 300n. The grant-free transmissions from the active set of client devices are thereafter jointly decoded. The active set of client devices may be determined by detecting the presence of client devices, e.g. via testing the presence of its signature which comprises its temporary transmission unit identity. Further, after having determined the active set of client devices, the network node 100 may remap the one or more TUs onto the one or more physical RUs if a number of data decoding failures corresponding to the active set of client devices exceeds a data decoding failure threshold value. The re-mapping is signalled to the client devices 300a, 300b,..., 300n in updated mapping information UMI as illustrated in Fig. 5. The data decoding failure threshold value may e.g. depend on system operation point and/or system target. For example, in some use cases the system can allow higher collision rate to keep connection capacity high, while in other use cases the system could operate in more reliable regime by keeping collision rate low at cost of reduce connection capacity.

While other types of client device identity (ID), such as manufactory ID, or Radio Network Temporary Identifier (RNTI), could be a long sequence within a large sequence space, such grouping of active set of client devices helps to reduce blind decoding complexity by searching only within pool of client devices attached to TUs. Instead of running blind decoding as for LTE DL control channel, the network node 100 can first run blind detection to identify active client devices and then run joint decoding based on list of active client devices. In this way the search space could be reduced significantly thereby reducing blind decoding complexity. The present temporary transmission unit identity for each client device could be signalled to the client devices via any of higher layer (RRC), MAC-CE, and L1 .

Moreover, the CQI used for mapping may be obtained in a number of different ways by the network node 100. In one embodiment, the CQIs associated with the client devices 300a, 300b,..., 300n are determined based on reference signals received from the client devices 300a, 300b,..., 300n (this is not illustrated in Fig. 5). Further, the reference signals may also be used by the network node 100 for determining modulation and coding rates (MCR) associated with the client devices 300a, 300b,..., 300n. The determined MCRs are transmitted to the client devices 300a, 300b,..., 300n in modulation and coding rate information (MCRI) from the network node 100. Depending on service classes and client device capabilities, the client devices 300a, 300b,..., 300n can in one example transmit sounding reference signals to the network node 100 to measure UL channel conditions so as to derive the CQI. Sounding reference signal could be a specific beacon for UL channel sounding, or other UL signals, e.g. UL demodulation reference signals. Sounding reference signal could be transmitted in separate time-frequency resources, or embedded in UL channels. The bandwidth of the sounding reference signal could be configured as wideband or sub-band signals, i.e. spans all possible RUs or only a subset of the RUs. The transmission power of the sounding reference signal could be independent of UL traffic and control channel or tied to them as in LTE. The sounding reference signals could be configured in a variety of ways by the network node 100, such as e.g. including system information block, higher layer RRC signalling, MAC-CE, and physical layer signalling, such as L1 . Hence, the network node 100 may configure the sounding reference signals transmitted by the client devices to the network node 100.

The network node 100 measures UL reference signals to estimate channel quality associated with the client devices 300a, 300b,..., 300n, and allocates client devices 300a, 300b,..., 300n to favourable RUs to achieve multiuser diversity (frequency-selective scheduling). The network node 100 can also control modulation and rate (such as MCS) based on UL reference signals. Both user allocation and rate control messages can also be delivered to client devices via similar mechanism as mapping or re-mapping, i.e. system information block, higher layer RRC signalling, MAC-CE, and physical layer signalling, such as L1 . Fig. 6 illustrates classification of applications and the mapping of TU onto physical RUs based on the classification. The network node 100 maintains a pool of TUs for grant-free UL transmissions, including both mMTC and URLLC services, in this example. The TUs in the pool can be categorized into Contention-Based (CBTU) and Contention-Free (CFTU) serving non-mission critical mMTC and critical URLLC client devices, respectively. During service request, applications are attached to TUs depending on service classes and its requirements. For example, sensor type of services could be allocated to CBTU, while industrial control services could be allocated to CFTU. The TUs are mapped to physical RUs, including e.g. time, frequency, signature, power, and reference signals. The size of the TU pool depends on system loading of all services including enhanced Mobile Broad Band (eMBB), mMTC and URLLC. A RU in the pool of RUs can have the same size as a resource block (RB), or have a different size. Bundling of RUs in the time and/or frequency domain is possible, and may depend on the service class. For example, in some mMTC applications in which extended coverage is required, the RUs could span longer in the time domain, while narrower in frequency domain. As another example, in URLLC applications, the RUs could span very short in the time domain, while longer in the frequency domain to reduce latency. In other scenarios, mapping of TUs to physical RUs could also be spread in the time and frequency plane to achieve diversity which is more described below.

Further, TU to RU mapping could be either localized in time-frequency resources, or distributed in time and/or frequency. The network node 100 can re-map the TU to RU periodically or triggered by an event such as overloading; for achieving diversity; for interference management; or for loading balancing. Note that frequency hopping can be viewed as a special case of re-mapping in this context.

Fig. 7 shows temporal distributed mapping of TU to RU; Fig. 8 shows a frequency domain distributed mapping; and Fig. 9 shows time-frequency distributed mapping. Different TU could be multiplexed in time division multiplexing (TDM), in frequency division multiplexing (FDM) or in a hybrid TDM and FDM fashion.

Fig. 7 illustrates mapping of TUs to time-frequency RUs for coverage enhancement with TDM or bundled transmission interval. The x-axis shows time and the y-axis frequency. As can be seen in Fig. 7 the different RUs are non-overlapping in the time dimension.

Fig. 8 illustrates mapping of TUs to time-frequency RUs for low latency with FDM or wide frequency allocation and short transmission interval. The x-axis shows time and the y-axis frequency. As can be seen in Fig. 8 the different RUs are non-overlapping in the frequency dimension.

Fig. 9 illustrates mapping of TU to time-frequency resource for time-frequency diversity where RUs are scattered in time and frequency. The x-axis shows time and the y-axis frequency. As can be seen in Fig. 9 the different RUs are non-overlapping in the frequency dimension or in the time dimension.

In case of retransmission by the client device 300, there could be a variety of mapping options. For example, the client device 300 can use the same RU(s) as used in the first grant-free transmission, until system remapping order from network node 100. However, the client device 300 could instead use a predefined different RU or CFTU for retransmission. The RU(s) used for retransmission could be signalled to the client device 300 via system information block (SIB), higher layer RRC signalling, MAC-CE, and physical layer signalling, such as L1 . Furthermore, in order to balance network load and manage inter-cell interference in a cellular type of wireless communication system 500, further embodiments of the invention are hereinafter disclosed some of which are illustrated in Fig. 10.

As shown in Fig. 10 the network nodes of the wireless communication system 500 are configured to communicate with each other, e.g. via backhaul signalling. In this respect a backhaul interface 502 is provided for the backhaul signalling. The backhaul interface 502 is illustrated with the dashed and dotted lines between the network nodes in Fig. 10. One general network mechanism for handling load balancing and inter-cell interference management is information exchange between the network nodes of the wireless communication system 500 by network signalling. Therefore, in one embodiment, the network node 100 signals at least one of the mapping information Ml, the updated mapping information UMI, the identity information IDI, and the modulation and coding rate information MCRI to one or more other network nodes 100a^', 100b^',..., 100n^' in the wireless communication system 500 via the backhaul interface 502. The other network nodes 100a^', 100b^',..., 100n^' could accordingly adjust their communication with the client devices served by them.

In one embodiment, the issue of intra-cell load balancing is considered. In this case the network node 100 obtains a first set of measurements associated with client devices 300a, 300b,..., 300n severed by the network node 100 itself (see Fig. 5). Examples are Interference over Thermal (loT) over RU, which is a measure of interference level, collision based on ACK/NACK, etc. but is not limited thereto. Based on the first set of measurements the network node 100 re-maps the one or more TUs onto the one or more physical RUs. This re-mapping may e.g. be conditioned on if it is determined that overloading has occurred. The re-mapping is thereafter signalled to the other network nodes 100a^', 100b^',..., 100n via the backhaul interface 502.

The network node 100 may obtain a second set of measurements for one or more client devices 300a^', 300b^',..., 300n^' served by the one or more other network nodes 100a^', 100b^',..., 100n^' as illustrated in Fig. 10. The second set of measurements may also in this case relate to Interference over Thermal (loT) over RU, collision based on ACK/NACK, etc. The network node 100 is configured to signal a RU overloading indicator (Ol) to the one or more other network nodes 100a^', 100b^',..., 100n^' if at least one measured value of the second set of measurements exceeds a measurement threshold value to request for reducing loading on impacted RU. The measurement threshold value may depend on system operation point and/or system target. For example, in some use cases the system can allow higher interference level and/or collision rate to keep connection capacity high, while in other use cases the system would operate in more reliable regime by keeping interference level and/or collision rate low at cost of reduce connection capacity.

Furthermore, the network node 100 can also inform the other network nodes 100a^', 100b^',..., 100n of possible overloading in some RUs via RU High Interference Indicator (HII) signalling. Thereby, the other network nodes 100a^', 100b^',..., 100n can adjust their mapping accordingly. In one embodiment the signalling of the HII is based on at least one of the mapping information Ml, the updated mapping information UMI, the identity information ID I , and the modulation and coding rate information MCRI. For example, the network node 100 can inform the other (neighbour) network nodes 100a^', 100b^',..., 100n to expect high interference at some RUs. Furthermore, the issue of inter-cell interference mitigation can be considered. If the network nodes in the wireless communication system 500 exchange configurations of TU and/or RU, including client device signatures and pilot sequences, it is possible for the network node 100 to run advanced receiver algorithms, such as joint detection or interference cancellation. Furthermore, any method according to embodiments of the invention may be implemented in a computer program, having code means, which when run by processing means causes the processing means to execute the steps of the method. The computer program is included in a computer readable medium of a computer program product. The computer readable medium may comprises essentially any memory, such as a ROM (Read-Only Memory), a PROM (Programmable Read-Only Memory), an EPROM (Erasable PROM), a Flash memory, an EEPROM (Electrically Erasable PROM), or a hard disk drive.

Moreover, it is realized by the skilled person that embodiments of the network node 100 and client device 300 comprises the necessary communication capabilities in the form of e.g., functions, means, units, elements, etc., for performing the present solution. Examples of other such means, units, elements and functions are: processors, memory, buffers, control logic, encoders, decoders, rate matchers, de-rate matchers, mapping units, multipliers, decision units, selecting units, switches, interleavers, de-interleavers, modulators, demodulators, inputs, outputs, antennas, amplifiers, receiver units, transmitter units, DSPs, MSDs, TCM encoder, TCM decoder, power supply units, power feeders, communication interfaces, communication protocols, etc. which are suitably arranged together for performing the present solution.

Especially, the processor 102, 302 of the network node 100 and client device, respectively, may comprise, e.g., one or more instances of a Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The expression "processor" may thus represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above. The processing circuitry may further perform data processing functions for inputting, outputting, and processing of data comprising data buffering and device control functions, such as call processing control, user interface control, or the like. Finally, it should be understood that the invention is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.

Claims

1 . A network node (100) for a wireless communication system (500), the network node (100) comprising

a processor (102) configured to

classify one or more applications associated with one or more client devices (300a, 300b,..., 300n) into one or more service classes, wherein each service class corresponds to a Quality of Service, QoS, requirement,

group applications in a service class into one or more transmission units for the service class,

map the one or more transmission units for the service class onto one or more physical resource units based on at least one of the QoS requirement for the service class and a channel quality information associated with the one or more client devices (300a, 300b,..., 300n), wherein the one or more physical resource units are assigned for grant-free transmissions from the one or more client devices (300a, 300b,..., 300n) to the network node (100),

a transceiver (104) configured to

signal a mapping information (Ml) to the one or more client devices (300a, 300b,..., 300n), wherein the mapping information (Ml) comprises the mapping of the one or more transmission units for the service class onto the one or more physical resource units.

2. The network node (100) according to claim 1 , wherein the processor (102) is configured to assign a temporary transmission unit identity for each client device of the one or more client devices (300a, 300b,..., 300n),

wherein the transceiver (104) is configured to

signal an identity information ( ID I) to the one or more client devices (300a, 300b,...,

300n), wherein the identity information (IDI) comprises the temporary transmission unit identity.

3. The network node (100) according to claim 2, wherein the transceiver (104) is configured to

receive grant-free transmissions from the one or more client devices (300a, 300b,..., 300n) in the mapped one or more physical resource units, wherein the grant-free transmissions comprises one or more temporary transmission unit identities,

wherein the processor (102) is configured to

determine an active set of client devices among the one or more client devices (300a,

300b,..., 300n) based on the one or more temporary transmission unit identities,

decode the grant-free transmissions from the active set of client devices.

4. The network node (100) according to claim 3, wherein the processor (102) is configured to re-map the one or more transmission units onto the one or more physical resource units if a number of data decoding failures corresponding to the active set of client devices exceeds a data decoding failure threshold value,

wherein the transceiver (104) is configured to

signal an updated mapping information (UMI) to the one or more client devices (300a, 300b,..., 300n), wherein the updated mapping information (UMI) comprises the re-mapping of the one or more transmission units onto the one or more physical resource units.

5. The network node (100) according to any of the preceding claims, wherein the transceiver (104) is configured to

receive one or more reference signals from the one or more client devices (300a, 300b,..., 300n),

wherein the processor (102) is configured to

determine the channel quality information and a modulation and coding rate associated with the one or more client devices (300a, 300b,..., 300n) based on the received one or more reference signals,

signal a modulation and coding rate information (MCRI) to the one or more client devices (300a, 300b,..., 300n), wherein the modulation and coding rate information (MCRI) comprises the modulation and coding rate.

6. The network node (100) according to any of the preceding claims, wherein the processor (102) is configured to

obtain a first set of measurements, wherein the first set of measurements comprises one or more measured values associated with at least one of the one or more resource units, the one or more client devices (300a, 300b,..., 300n), and the service class,

wherein the transceiver (104) is configured to

7. The network node (100) according to any of the preceding claims, wherein the transceiver (104) is configured to signal at least one of the mapping information (Ml), the updated mapping information (UMI), the identity information (IDI), and the modulation and coding rate information (MCRI) to the one or more client devices (300a, 300b,..., 300n) via at least one of radio resource control, a medium access control element, system information block, and physical layer signaling.

8. The network node (100) according to any of the preceding claims, wherein the transceiver (104) is configured to

signal at least one of the mapping information (Ml), the updated mapping information (UMI), the identity information (IDI), and the modulation and coding rate information (MCRI) to one or more other network nodes (100a^', 100b^',..., 100n^').

9. The network node (100) according to claim 8, wherein the processor (102) is configured to obtain a second set of measurements for one or more client devices (300a^', 300b^',..., 300n^') served by the one or more other network nodes (100a^', 100b^',..., 100n^'), wherein the second set of measurements comprises one or more measured values associated with at least one of the one or more resource units, the one or more client devices (300a, 300b,..., 300n), and the service class,

wherein the transceiver (104) is configured to

signal a resource unit overloading indicator (Ol) to the one or more other network nodes (100a^', 100b^',..., 100n^') if a measured value of the second set of measurements exceeds a measurement threshold value.

10. The network node (100) according to claim 8 or 9, wherein the transceiver (104) is configured to

signal a resource unit high interference indicator (HI I) to the one or more other network nodes (100a^', 100b^',..., 100n^') based on at least one of the mapping information (Ml), the updated mapping information (UMI), the identity information (IDI), and the modulation and coding rate information (MCRI).

1 1 . A client device (300) for a wireless communication system (500), the client device (300) comprising

a processor (302) configured to

a transceiver (304) configured to receive a mapping information (Ml) from a network node (100), wherein the mapping information (Ml) comprises a mapping of one or more transmission units onto one or more physical resource units for grant-free transmission,

transmit data to the network node (100) in the one or more physical resource units based on the mapping information (Ml), wherein the data is associated with the one or more applications.

12. The client device (300) according to claim 1 1 , wherein the transceiver (304) is configured to

receive an identity information (IDI) from the network node (100), wherein the identity information (IDI) comprises temporary transmission unit identity for the client device (100), include the temporary transmission unit identity in the data transmitted to the network node (100) in the one or more physical resource units for grant-free transmission.

13. The client device (300) according to claim 1 1 or 12, wherein the transceiver (304) is configured to

receive an updated mapping information (UMI) from the network node (100), wherein the updated mapping information (UMI) comprises re-mapping of the one or more transmission units onto the one or more physical resource units for grant-free transmission,

retransmit the data in the one or more physical resource units based on the updated mapping information (UMI).

14. Method for a network node (100), the method (200) comprising:

classifying (202) one or more applications associated with one or more client devices (300a, 300b,..., 300n) into one or more service classes, wherein each service class corresponds to a Quality of Service, QoS, requirement,

grouping (204) applications in a service class into one or more transmission units for the service class,

mapping (206) the one or more transmission units for the service class onto one or more physical resource units based on at least one of the QoS requirement for the service class and a channel quality information associated with the one or more client devices (300a, 300b,..., 300n), wherein the one or more physical resource units are assigned for grant-free transmissions from the one or more client devices (300a, 300b,..., 300n) to the network node (100),

signaling (208) a mapping information (Ml) to the one or more client devices (300a,

300b,..., 300n), wherein the mapping information (Ml) comprises the mapping of the one or more transmission units for the service class onto the one or more physical resource units.

15. Method for a client device (300), the method (400) comprising:

running (402) one or more applications, wherein each application is associated with a QoS requirement,

receiving (404) a mapping information (Ml) from a network node (100), wherein the mapping information (Ml) comprises a mapping of one or more transmission units onto one or more physical resource units for grant-free transmission,

transmitting (406) data to the network node (100) in the one or more physical resource units based on the mapping information (Ml), wherein the data is associated with the one or more applications.

16. Computer program with a program code for performing a method according to claim 14 or 15 when the computer program runs on a computer.