Technical Field

The invention relates to a network access node and a client device for efficient control channel reception. Furthermore, the invention also relates to corresponding methods and a computer program.

Background

In 3GPP Release 15, a couple of control channel configuration and scheduling cases were identified causing ambiguity in the signal reception at the receiver. In particular the control channel of aggregation level 8 or 16 (AL 8 or AL 16), under certain transmission settings, such as the AL 8 and AL 16 control channel candidates having same starting control channel element (CCE) and share CCEs, could be ambiguously received as either aggregation level 16 or aggregation level 8. For example, when the gNB is using AL 16 for the transmission of a physical downlink control channel (PDCCH) candidate, the user equipment (UE) may wrongly detect it as AL 8. The UE will then perform rate matching around the wrong resources and would possibly not be able to decode the physical downlink shared channel (PDSCH). The wrong rate matching pattern will not only decrease the performance of the current PDSCH transmission, but also the retransmission due to wrong soft values in the log likelihood ratio (LLR) buffer.

In new radio (NR) as opposed to long term evolution (LTE), a dynamic re-use of control resources is supported. A control resource set (CORESET) defines the time-frequency region in which PDCCHs may be transmitted. A CORESET can span up to 3 symbols and the entire bandwidth and can be transmitted anywhere in the slot. If e.g. only one PDCCH is transmitted in the CORESET, then in most cases it will not occupy all of its resources. The remaining resources can then dynamically be re-used by the data channel, i.e. PDSCH. This dynamic resource sharing is already important for enhanced mobile broadband (eMBB) applications’ efficiency, but it becomes essential for ultra reliable low latency communication (URLLC) applications. In URLLC, the control channel will be monitored several times (e.g. 7 times) during a slot.

The CORESET has a duration of one OFDM symbol. The gNB transmits a PDCCH with AL16, rate-matches around the scheduling PDCCH and maps the PDSCH on the 16 unoccupied CCEs in the CORESET. The receiver however, due to the ambiguity, might identify it as a control channel of AL 8. It will then assume that PDSCH is mapped on the resources of the CORESET on which the gNB in fact has transmitted a PDCCH, which leads to data channel reception quality degradation.

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 efficient control channel reception compared to conventional solutions.

The above and further objectives are solved by the subject matter of the independent claims. Further advantageous embodiments 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 access node for a wireless communication system, the network access node being configured to

obtain an aggregation level associated with a physical downlink control channel;

generate a control message comprising an indication of the aggregation level;

provide the control message to a client device.

An aggregation level can in this disclosure have the meaning as defined by a standard. In NR an aggregation level indicates how many control channel elements that are allocated for a physical downlink control channel. Hence, higher aggregation level means more coding and therefore lower code rate. Providing a control message can herein mean that the network access node is configured to transmit mentioned control message, e.g. in signaling. Further, control message has to be understood here in his broadest meaning of information which can be provided in a dedicated message but also information incorporated in existing messages or signals.

An advantage of the network access node according to the first aspect is that the physical downlink control channel can be received unambiguously. More specifically, the problem of control channel reception ambiguity if it is not solved adequately will have as a result waste of data channel resources, system latency increase, and possible data channel performance degradation. It may ultimately lead to breaking the URLLC latency requirements and/or reliability requirements and severely constraint the URLLC system capacity. In an implementation form of a network access node according to the first aspect, the network access node is further configured to

adapt a data transmission to the client device according to the indicated aggregation level;

perform the adapted data transmission to the client device.

Rate matching herein can mean that puncturing and/or (zero) padding is performed if needed on data packets of the data transmission, and that the data packets are allocated on time and frequency resources around the resources for the physical downlink control channel.

An advantage with this implementation form is that the data channel reception will not suffer from client device confusing the control channel resources to data channel resources. Therefore, the data channel can be scheduled in the same symbol(s) as the control channel or at least immediately after the control channel, thereby reducing latency of data channel transmission and increasing resource utilization in the wireless communication system.

In an implementation form of a network access node according to the first aspect, the network access node is further configured to

transmit the control message to the client device in the physical downlink control channel; perform the data transmission to the client device in a physical downlink shared channel associated with the physical downlink control channel.

An advantage with this implementation form is that the client device will know which physical downlink shared channel that is associated to the physical downlink control channel and thereby reducing the complexity in the data decoding in the client device. Hence, there is no need for blind search of physical downlink shared channel by the client device.

In an implementation form of a network access node according to the first aspect, the control message is downlink control information comprising a plurality of information fields.

An advantage with this implementation form is that it gives information about the data transmission in the physical downlink shared channel. This means reduced complexity since the client device does not need to perform blind decoding and blind search when decoding the physical downlink shared channel. In an implementation form of a network access node according to the first aspect, the aggregation level is indicated with one or more bits in a dedicated information field of the downlink control information.

An advantage with this implementation form is that this is low complex solution to indicate the aggregating level implying spectral efficient signalling.

In an implementation form of a network access node according to the first aspect, wherein the indicated aggregation level is aggregation level 8 or aggregation level 16 indicated with a single bit.

This implementation form is a spectral efficient signalling solution.

In an implementation form of a network access node according to the first aspect, the aggregation level is explicitly indicated with a plurality of bits.

An advantage with this implementation form is that this is a low complex solution for indicating the aggregation level.

In an implementation form of a network access node according to the first aspect, the aggregation level is indicated with a scrambled cyclic redundancy check word of the downlink control information.

An advantage with this implementation form is that no information field in downlink control information is needed for indicating the aggregation level. Hence, old downlink control information formats can be reused which reduces the number of blind searches since there are fewer downlink control information format that the client device need to search for.

In an implementation form of a network access node according to the first aspect, the downlink control information has a format dependent on the service type of the data transmission to the client device.

An advantage with this implementation form is that the downlink control information can be optimized for different service types resulting in a spectral efficient solution. In an implementation form of a network access node according to the first aspect, the downlink control information is common to a group of client devices or dedicated for a single client device.

An advantage with this implementation form is that the solution is applicable to both dedicated and common downlink control information signalling resulting in an efficient solution minimizing the signalling overhead.

In an implementation form of a network access node according to the first aspect, the indicated aggregation level is associated with the control message.

An advantage with this implementation form is that the client device can verify the received indicated aggregation level and therefrom know where the resources of the physical downlink shared channel are allocated. This reduces the decoding error rate for the physical downlink shared channel.

In an implementation form of a network access node according to the first aspect, the control message comprises a reference signal sequence indicating the aggregation level.

An advantage with this implementation form is that no information field in downlink control information is needed for indicating the aggregation level. Hence, old downlink control information formats can be reused which reduces the number of blind searches since there are fewer downlink control information format that the client device need to search for.

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 being configured to

obtain a control message from a network access node, wherein the control message comprises an indication of an aggregation level associated with a physical downlink control channel;

obtain the indicated aggregation level from the control message.

Obtaining a control message can herein mean that the client is configured to receive mentioned control message, e.g. in signaling from the network access node. Further, control message has to be understood here in his broadest meaning of information which can be provided in a dedicated message but also information incorporated in existing messages or signals. An advantage of the client device according to the second aspect is that the physical downlink control channel can be received unambiguously. More specifically, the problem of control channel reception ambiguity if it is not solved adequately will have as a result waste of data channel resources, system latency increase, and possible data channel performance degradation. It may ultimately lead to breaking the URLLC latency requirements and/or reliability requirements and severely constraint the URLLC system capacity.

In an implementation form of a client device according to the second aspect, the client device is further configured to

receive a data transmission from the network access node;

adapt decoding of the data transmission according to the obtained aggregation level.

Adapt decoding of the data transmission can herein mean that the client device selects resources outside the detected aggregation level for the physical downlink control channel and decode said resources for the data transmission.

An advantage with this implementation form is that the data channel reception will not suffer from client device confusing the control channel resources to data channel resources. Therefore, the data channel can be scheduled in the same symbol(s) as the control channel or at least immediately after the control channel, thereby reducing latency of data channel transmission and increasing resource utilization in the wireless communication system.

In an implementation form of a client device according to the second aspect, the client device is further configured to

receive the control message in the physical downlink control channel;

receive the data transmission in a physical downlink shared channel associated with the physical downlink control channel.

An advantage with this implementation form is that the client device will know which physical downlink shared channel that is associated to the physical downlink control channel and thereby reducing the complexity in the data decoding in the client device. Hence, there is no need for blind search of physical downlink shared channel by the client device.

In an implementation form of a client device according to the second aspect, the control message is downlink control information comprising a plurality of information fields. An advantage with this implementation form is that it gives information about the data transmission in the physical downlink shared channel. This means reduced complexity since the client device does not need to perform blind decoding and blind search when decoding the physical downlink shared channel.

In an implementation form of a client device according to the second aspect, the aggregation level is indicated with one or more bits in a dedicated information field of the downlink control information.

An advantage with this implementation form is that this is low complex solution to indicate the aggregating level implying spectral efficient signalling.

In an implementation form of a client device according to the second aspect, the indicated aggregation level is aggregation level 8 or aggregation level 16 indicated with a single bit.

This implementation form is a spectral efficient signalling solution.

In an implementation form of a client device according to the second aspect, the aggregation level is explicitly indicated with a plurality of bits.

An advantage with this implementation form is that this is a low complex solution for indicating the aggregation level.

In an implementation form of a client device according to the second aspect, the aggregation level is indicated with a scrambled cyclic redundancy check word of the downlink control information.

An advantage with this implementation form is that no information field in downlink control information is needed for indicating the aggregation level. Hence, old downlink control information formats can be reused which reduces the number of blind searches since there are fewer downlink control information format that the client device need to search for.

In an implementation form of a client device according to the second aspect, the indicated aggregation level is associated with the control message.

An advantage with this implementation form is that the client device can verify the received indicated aggregation level and therefrom know where the resources of the physical downlink shared channel are allocated. This reduces the decoding error rate for the physical downlink shared channel.

In an implementation form of a client device according to the second aspect, the control message comprises reference signals indicating the aggregation level.

An advantage with this implementation form is that no information field in downlink control information is needed for indicating the aggregation level. Hence, old downlink control information formats can be reused which reduces the number of blind searches since there are fewer downlink control information format that the client device need to search for.

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

obtaining an aggregation level associated with a physical downlink control channel; generating a control message comprising an indication of the aggregation level;

transmitting the control message to a client device.

The method according to the third aspect can be extended into implementation forms corresponding to the implementation forms of the network access node according to the first aspect. Hence, an implementation form of the method comprises the feature(s) of the corresponding implementation form of the network access node.

The advantages of the methods according to the third aspect are the same as those for the corresponding implementation forms of the network access node according to the first aspect.

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 comprises

receiving a control message from a network access node, wherein the control message comprises an indication of an aggregation level associated with a physical downlink control channel;

obtaining the indicated aggregation level from the control message.

The method according to the fourth aspect can be extended into implementation forms corresponding to the implementation forms of the client device according to the second aspect. Hence, an implementation form of the method comprises the feature(s) of the corresponding implementation form of the client device. The advantages of the methods according to the fourth aspect are the same as those for the corresponding implementation forms of the client device according to the second aspect.

The invention also relates to a computer program, characterized in program code, which when run by at least one processor causes said at least one processor to execute any method according to embodiments of the 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 embodiments of the 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 invention, in which:

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

- Fig. 2 shows a method for a network access node 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 for a client device according to an embodiment of the invention;

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

- Fig. 6 shows a flow chart of a method for the network access node according to an embodiment of the invention; and

- Fig. 7 shows a flow chart of a method for the client device according to an embodiment of the invention.

Detailed Description

A solution was introduced in Release 15 TS38.214 section 5.1.4.1 v15.3.0 to the AL 8 and AL 16 ambiguity previously discussed. In this solution, if a UE monitors PDCCH candidates of AL 8 and AL 16 with the same starting CCE index in non-interleaved CORESET spanning one OFDM symbol and if a detected PDCCH scheduling the PDSCH has AL 8, the resources corresponding to the AL 16 PDCCH candidate are not available for the PDSCH. This method achieves common understanding between gNB and UE about the PDSCH mapping, but according to the inventors of the present invention mentioned conventional solution will lead to waste of valuable resources for the PDSCH when a PDCCH with AL 8 is scheduled, i.e. 8 CCE = 48 PRB, and also it leads to system latency increase. Furthermore, it is only applicable to certain configurations and not covering all scenarios in which the said AL 8/ AL16 ambiguity occurs. Furthermore, more scenarios have been observed by the inventors where once the starting CCEs of AL 8 and AL 16 candidates are the same, the ambiguity would occur. The solution of Release 15 resolves the control channel ambiguity in the receiver, yet it causes a substantial waste of data resources, possible data channel reception quality degradation, and latency increase. Additionally, AL 8 and AL 16 are essential to ensure high PDCCH reliability for URLLC. Moreover, the PDSCH for URLLC has to be scheduled as early as possible (in to the same OFDM symbol, if possible, as the PDCCH) to achieve the low latency requirement and avoid wasting unoccupied resources. Therefore, there is a need for method and apparatus for solving these and further issues in further releases of the NR standard in a more efficient way.

Fig. 1 shows a network access node 100 according to an embodiment of the invention. In the embodiment shown in Fig. 1 , the network access node 100 comprises a processor 102, a transceiver 104 and a memory 106. The processor 102 is coupled to the transceiver 104 and the memory 106 by communication means 108 known in the art. The network access node 100 may be configured for both wireless and wired communications in wireless and wired communication systems, respectively. The wireless communication capability is provided with an antenna or antenna array 1 10 coupled to the transceiver 104, while the wired communication capability is provided with a wired communication interface 1 12 coupled to the transceiver 104. That the network access node 100 is configured to perform certain actions can in this disclosure be understood to mean that the network access node 100 comprises suitable means, such as e.g. the processor 102 and the transceiver 104, configured to perform said actions.

According to embodiments of the invention the network access node 100 is configured to obtain an aggregation level associated with a PDCCH. The network access node 100 is further configured to generate a control message 510 (shown in Fig. 5) comprising an indication of the aggregation level and transmit the control message 510 to a client device 300.

Fig. 2 shows a flow chart of a corresponding method 200 which may be executed in a network access node 100, such as the one shown in Fig. 1. The method 200 comprises obtaining 202 an aggregation level associated with a PDCCH. The method 200 further comprises generating 204 a control message 510 comprising an indication of the aggregation level and transmitting 206 the control message 510 to a client device 300.

Fig. 3 shows a client device 300 according to an embodiment of the invention. In the embodiment shown in Fig. 3, the client device 300 comprises a processor 302, a transceiver 304 and a memory 306. The processor 302 is coupled to the transceiver 304 and the memory 306 by communication means 308 known in the art. The client device 300 further comprises an antenna or antenna array 310 coupled to the transceiver 304, which means that the client device 300 is configured for wireless communications in a wireless communication system 500. That the client device 300 is configured to perform certain actions can in this disclosure be understood to mean that the client device 300 comprises suitable means, such as e.g. the processor 302 and the transceiver 304, configured to perform said actions.

According to embodiments of the invention the client device 300 is configured to receive a control message 510 from a network access node 100. The control message 510 comprises an indication of an aggregation level associated with a PDCCH. The client device 300 is further configured to obtain the indicated aggregation level from the control message 510.

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 receiving 402 a control message 510 from a network access node 100. The control message 510 comprises an indication of an aggregation level associated with a PDCCH. The method 400 further comprises obtaining 404 the indicated aggregation level from the control message 510.

Fig. 5 shows a wireless communication system 500 according to an embodiment of the invention. The wireless communication system 500 comprises a network access node 100 and a client device 300 configured to operate in the wireless communication system 500. For simplicity, the wireless communication system 500 shown in Fig. 5 only comprises one network access node 100 and one client device 300. However, the wireless communication system 500 may comprise any number of network access nodes 100 and any number of client devices 300 without deviating from the scope of the invention.

In the wireless communication system 500, the network access node 100 is connected to the client device 300. When the network access node 100 has a data transmission 512 to be transmitted to the client device 300, the network access node 100 first transmits a control message 510 to the client device 300, as shown in Fig. 5. The control message 510 may be transmitted in a PDCCH and indicates the aggregation level associated with the PDCCH. The network access node 100 further transmits the data transmission 512 to the client device 300, as shown in Fig. 5. In embodiments, the aggregation level associated with the PDCCH is aggregation level 8 or aggregation level 16. Thus, with the control message 510 the network access node 100 may inform the client device 300 whether aggregation level 8 or aggregation level 16 is used for the PDCCH. Thereby, the client device 300 is able to correctly decode the data transmission 512 received from the network access node 100.

Fig. 6 shows a flow chart of a method 600 according to an embodiment of the invention which may be executed in the network access node 100, when the network access node 100 is connected to the client device 300. Connected herein can imply that the client device 300 is in connected mode, i.e. RRC_Connected, and has an active communication ongoing with the network access node 100.

In step 602, the network access node 100 determines that a data transmission should be performed to the client device 300.

Upon determining that the data transmission should be performed, the network access node 100 obtains an aggregation level associated with a PDCCH in step 604. The aggregation level may e.g. be obtained based on received channel state information (CSI) reports from the client device 300 indicating the modulation and coding scheme (MCS) needed for reliable transmission of the PDCCH. The aggregation level can also be determined based on other parameters directly or indirectly indicating the channel quality between the network access node 100 and the client device 300.

In step 606, the network access node 100 generates a control message 510 comprising an indication of the obtained/determined aggregation level. In embodiments, the control message 510 is downlink control information (DCI) comprising a plurality of information fields. In this case, the aggregation level may be indicated with one or more bits in a dedicated information field of the DCI. A dedicated information field in this case means that it is only used for indicating aggregation levels. Furthermore, other bits in information fields of the DCI are obtained, coded, and allocated to time and/or frequency resources according to the obtained aggregation level. The indicated aggregation level is associated with the control message 510.

In step 608, the network access node 100 transmits the control message 510 to the client device 300. The network access node 100 may transmit the control message 510 to the client device 300 in the PDCCH. In step 610, the network access node 100 adapts the data transmission to the client device 300 according to the indicated aggregation level and performs the adapted data transmission to the client device 300. That the network access node 100 adapts the data transmission can in this disclosure be understood to mean that the network access node 100 rate matches the data transmission. Rate matching herein can mean that puncturing and/or (zero) padding is performed if needed on data packets of the data transmission, and that data packets are allocated on time and frequency resources around the resources for the physical downlink control channel. The network access node 100 may perform the data transmission to the client device 300 in a PDSCH associated with the PDCCH. In embodiments of the invention, the network access node 100 may hence perform rate matching of the PDSCH according to the indicated aggregation level associated with the PDCCH. The network access node 100 further allocates resources for the data transmission and performs the rate matched data transmission in the PDSCH to the client device 300.

Fig. 7 shows a flow chart of a method 700 according to an embodiment of the invention which may be executed in the client device 300, when the client device 300 is connected to the network access node 100.

In step 702, the client device 300 receives a control message 510 from the network access node 100. The control message 510 comprises an indication of an aggregation level associated with a PDCCH. In embodiments, the client device 300 may receive the control message 510 in the PDCCH. In this case, the client device 300 may monitor a PDCCH search space according to a configuration received from the network access node 100 and detect the control message 510 in the PDCCH based on the monitoring. For example, in NR the client device 300 is configured with a CORSET to perform search for DCI. The client device 300 performs blind decoding and tests different aggregation levels on different positions for detecting the DCI. Once a CRC of a decoding is checked the DCI is detected.

In step 704, the client device 300 obtains the indicated aggregation level from the control message 510. Thus, from the control message 510 the client device 300 determines/derives the aggregation level associated with the PDCCH. As described above with reference to step 606 in Fig. 6, the control message 510 is in embodiments of the invention a DCI comprising a plurality of information fields and the aggregation level may be indicated with one or more bits in a dedicated information field of the DCI. In such embodiments, the client device 300 may hence obtain/derive the aggregation level from the dedicated information field of the DCI. In step 706, the client device 300 receives a data transmission from the network access node 100. As described above with reference to step 610 in Fig. 6, the data transmission may be performed in a PDSCH associated with the PDCCH. Hence, the client device 300 may in embodiments receive the data transmission in the PDSCH associated with the PDCCH.

According to the aggregation level obtained in step 704, the client device 300 adapts decoding of the received data transmission in step 708. That the client device 300 adapt decoding of the data transmission can mean that the client device 300 rate matches which herein can mean that the client device 300 selects resources outside the detected aggregation level for the physical downlink control channel and decode said resources for the data transmission.

As aforementioned, in embodiments of the invention, the control message 510 is a DCI. In one example the DCI comprises a dedicated information field indicating the aggregation level. The dedicated information field may comprise a single bit or a plurality of bits. When the dedicated information field comprise a single bit, the dedicated information field can explicitly indicate two different aggregation levels or indicate whether a specific aggregation level has been used or not. For example, to indicate whether AL 8 or AL 16 is used, the single bit in the dedicated information field may be set to“0” if aggregation level 8 is used and to“1” if AL 16 is used. Alternatively, the single bit in the dedicated information field may be set to“0” if AL 16 is used and to“1” if AL 16 is not used, i.e. as a flag. In other words, the indicated aggregation level may be AL 8 or AL 16 and the aggregation level may be indicated with a single bit.

When the dedicated information field comprise a plurality of bit, the aggregation level may be explicitly indicated for any number of aggregation levels. For example, two bits can be used to indicate four different application levels, etc. Furthermore, two bits may be used to indicate whether aggregation level 8 or aggregation level 16 is used. In this case, the two bits in the dedicated information field may be set to“1 1” if aggregation level 8 is used and to“00” if aggregation level 16 is used, while“01” and“10” are reserved. In other words, in embodiments the aggregation level is explicitly indicated with a plurality of bits.

When the dedicated information field in the DCI is used, the aggregation level can be explicitly indicated to the client device 300. However, according to embodiments of the invention the aggregation level can instead be implicitly indicated to the client device 300 using different sequences detectable by the client device 300.

In such embodiments of the invention, the aggregation level may be indicated with a scrambled cyclic redundancy check (CRC) word of the DCI or a reference signal (RS) sequence. The control message 510 may hence comprise a scrambled cyclic redundancy check (CRC) word of the DCI or a RS sequence indicating the aggregation level. Thus, different scrambled CRC words or different RS sequences may be mapped to different aggregation levels such that the client device 300 by detecting the scrambled CRC word or the RS sequence can derive the aggregation level. For example, the control channel CRC can be scrambled with a bit sequence (mask) indicating the aggregation level or the RS sequence of the CORESET can be modified to indicate the aggregation level. The mapping can be predefined and given be the standard.

Moreover, the DCI may be common to a group of client devices or dedicated for a single client device. Thus, the DCI may be monitored by a group of client devices or by a single client device.

Furthermore, the DCI may have a format dependent on the service type of the data transmission to the client device 300. For example, the DCI format comprising the dedicated information field may be used for data transmissions associated with a specific service such as e.g. a URLLC service. The DCI comprising the dedicated information field can hence in embodiments be a URLLC specific DCI. The URLLC specific DCI may have a payload size which is lower or equal payload size to e.g. the DCI format 1 -0 or 1 -1 .

According to further embodiments of the invention, if the client device 300 detects a DCI assuming AL 8 while indication of the aggregation level in the DCI indicates AL 16, the client device 300 should interpret the DCI as correctly decoded and select PDSCH resources according to AL 16.

When AL 8 and AL 16 are not configured within the same CORESET, there is no ambiguity to resolve. In this case the aggregation level indication information bit(s) can be omitted from the DCI which reduces the DCI payload. However, it is not always desirable to reduce the DCI payload, because this would increase the number of required blind decodings (BDs) to be performed. Hence, to avoid an increase of blind decodings by keeping the same DCI size (i.e. not reducing the DCI payload), the content of the aggregation level indicator can also be re- interpreted for the case when AL 8 and AL 16 are not configured together. One example is to set the content of this bit field of the DCI to a fixed value, which would decrease the false alarm probability. Hence, the aggregation level indication bit(s) may, in case the client device 300 is not configured for say AL 16 but the DCI format configured is the new DCI format as disclosed by embodiments of the invention, be reused for other purposes. Non-limiting examples of other purposes for the reuse of aggregation level indication bit(s) could be:

• UL power boost indication. • Extending other information fields for instance to allow more flexibility in HARQ A/N feedback timing.

• Triggering an aperiodic Channel State Indication (CSI) report.

• Indication of position and/or resources for another DCI.

The use of the aggregation level indication bit(s) may be defined by a pre-defined rule given by a standard, or configured, e.g. in a RRC/MAC CE configuration message from the network access node 100. Therefore, the invention also relates to a client device 300 according to these embodiments.

A1. A client device for a wireless communication system, the client device being configured to receive a DCI from a network access node, wherein the DCI comprises at least one bit indicating aggregation level 8 or aggregation level 16 associated with a physical downlink control channel;

obtain the at least one bit from the DCI upon determine that the client device is not configured with aggregation level 8 or aggregation level 16;

obtain a configuration associated with the at least one bit;

perform based on the at least one bit and the obtained configuration at least one of uplink power boost according to the at least one bit,

determine HARQ A/N timing based on the at least one bit,

trigger an uplink aperiodic CSI report according to the at least one bit, and verify that the at least one bit is fixed according to a predefined rule.

A2. The client device according to A1 , configured to

obtain the configuration from a predefined rule; or

obtain the configuration from a control message received from the network access node.

A3. The client device according to A1 or A2, wherein the at least one bit is a single bit or a plurality of bits.

The client device 300 according to embodiments A1 -A3 can also be combined with the other embodiments of the invention.

The network access node 100 herein may also be denoted as a radio network access node, an access network access 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,“gNB”,“gNodeB”,“eNB”, “eNodeB”,“NodeB” or“B node”, depending on the technology and terminology used. The radio network access node 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 access 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 radio network access node may also be a base station corresponding to the fifth generation (5G) wireless systems.

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 this 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 UE 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.

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 comprise 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 access node 100 and the client device 300 comprises the necessary communication capabilities in the form of e.g., functions, means, units, elements, etc., for performing the 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 togetherfor performing the solution. Especially, the processor(s) of the network access node 100 and the client device 300 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.