WO2018086693A1

WO2018086693A1 - Transmitting device, receiving device and methods thereof

Info

Publication number: WO2018086693A1
Application number: PCT/EP2016/077271
Authority: WO
Inventors: Rama Kumar MOPIDEVI
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2016-11-10
Filing date: 2016-11-10
Publication date: 2018-05-17
Anticipated expiration: 2019-05-10

Abstract

The present invention relates to a transmitting device and a receiving device. The transmitting device (100) being configured to derive a minimum transport block size ( T_Min); assemble transport blocks by sequentially concatenating data packets having a size smaller than the minimum transport block size ( T_Min) into a transport block (TB) as long as a current size of the transport block (TB) is equal to or smaller than the minimum transport block size (T_Min), and by inserting each data packet having a size between the minimum transport block size (T_Max) and a maximum transport block size (T_Min) into a single separate transport block (TB); transmit the assembled transport blocks to a receiving device (300). The receiving device (300) being configured to derive a minimum transport block size (T_Min), transmit a control message (CM) to a transmitting device (100), wherein the control message (CM) indicates the minimum transport block size (T_Min), receive assembled transport blocks comprising data packets from the transmitting device (100) in response to the transmission of the control message (CM). Furthermore, the invention also relates to corresponding methods, a computer program, and a computer program product.

Description

TRANSMITTING DEVICE, RECEIVING DEVICE AND METHODS THEREOF

Technical Field

The invention relates to a transmitting device and a receiving device. Furthermore, the invention also relates to corresponding methods, a computer program, and a computer program product.

Background

Data traffic between a transmitting device and a receiving device in a wireless communication system, such as Long Term Evolution (LTE) and Wideband Code Division Multiple Access (WCDMA), is transferred over the radio interface in transport blocks. The transport blocks are assembled by the transmitting device, which then transmits the assembled transport blocks over the radio interface to the receiving device. The next generation wireless communication systems (such as 5G) are targeting increased data rates. Data rates of 20 Gbps in downlink and 10 Gbps in uplink have been discussed in 3GPP standards.

One factor affecting high data rates in a wireless communication system is the handling of the transport blocks. In order to achieve high data rates the transport blocks need to be handled in an efficient manner.

In Long Term Evolution (LTE) uplink data transfer, the User Equipment (UE) prepares transport blocks after receiving uplink (UL) grants from the network. After receiving the UL grant, Media Access Control (MAC) calculates the data to be transmitted from Radio Link Control (RLC) and requests RLC to submit the data. RLC then prepares RLC Protocol Data Unit (PDU) and submits it to MAC. After constructing the transport block, MAC will submit the data to the physical layer (PHY) for transfer over the radio interface. In summary, RLC prepares RLC PDU after uplink grant is received.

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 handling of transport blocks in wireless communication systems. 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 transmitting device for a wireless communication system, the transmitting device being configured to

derive a minimum transport block size;

assemble transport blocks by sequentially concatenating data packets having a size smaller than the minimum transport block size into a transport block as long as a current size of the transport block is equal to or smaller than the minimum transport block size, and by inserting each data packet having a size between the minimum transport block size and a maximum transport block size into a single separate transport block (without concatenation or segmentation);

transmit the assembled transport blocks to a receiving device. The current size of the transport block is the size including all the concatenated data packets in this transport block. Hence, the size of a transport block which comprises more than one data packet is not allowed to exceed the minimum transport block size.

For example, the maximum transport size could be predefined by the system (e.g. set by a standard and could also be dependent on the category of the transmitting device) or could be defined and adjusted by a lower layer (e.g. RLC performs the concatenation and MAC defines the maximum transport block size for example based on a received transmission grant).

Hence, embodiments of the present invention introduce a minimum transport block size. Data packets (such as service data unit SDUs from a higher layer) which exceed the minimum transport block size are not concatenated with other data packet but are encapsulated in a transport block as they are. Hence, in this case one transport block comprises only one data packet. Data packets below the minimum transport block size (short data packets) are concatenated with other short data packets but only as long as the resulting transport block size remains below or equal to the minimum transport block size.

The transmitting device according to the first aspect provides a number of advantages over conventional solutions. One such advantage is to leave the concatenation flexibility to the transmitting device and to concatenate short data packets. Another such advantage is to reduce overhead in the system, e.g. minimizing Sequence Number (SN) space or any other non-payload data in this context.

In a first possible implementation form of a transmitting device according to the first aspect, the transmitting device is configured to

stop concatenating data packets into a current transport block if a next to be concatenated data packet has a size larger than the remaining space in the current transport block until the minimum transport block size is reached;

concatenate the next to be concatenated data packet into a succeeding transport block.

The first implementation form offers the advantage of flexibility to the transmitting device which decide when to concatenate or not.

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

derive the remaining space based on a difference between the minimum transport block size and the current size of the transport block.

In the second implementation form, the transmitting device determines if the remaining space is enough to concatenate a new sequential data packet or not. Thereby, improved concatenation is possible. In a third possible implementation form of a transmitting device according to the first implementation form of the first aspect or to the first aspect as such, the transmitting device is configured to

derive the minimum transport block size based on a type of service associated with the data packets.

The advantage with the third implementation form is to adapt the minimum transport block size to different service types. For example, the minimum transport block size can be larger for enhance Mobile Broadband (eMBB) compared to that for machine to machine communications, etc. Hence, more efficient transmission with lower non-payload is possible in the wireless communication system.

In a further possible implementation form of a transmitting device according to the third implementation form of the first aspect, the type of service is any of: enhanced Mobile Broad Band, Ultra Reliable Low Latency Communications, and massive Machine Type Communications. In a fourth possible implementation form of a transmitting device according to any of the preceding implementation forms of the first aspect or to the first aspect as such, the transmitting device is configured to

receive one or more transmission grants from the receiving device, wherein each transmission grant grants a transmission of one or more transport blocks and indicates the maximum transport block size for such a transmission,

derive the maximum transport block size for the transport block based on at least one maximum transport block size indicated in the one or more transmission grants which will be used to transmit the transport block,

transmit the assembled transport blocks to the receiving device based on the one or more transmission grants.

The minimum transport block size may be obtained by the transmitting device before receiving the transmission grants. The fourth implementation form provides a dynamic updating mechanism for obtaining the maximum transport block size used in the concatenation performed by the transmitting device according to the first aspect. Thereby, assembly of the transport blocks can be adapted to traffic characteristics or channel conditions or any other information provided in the transmission grants for.

In a fifth possible implementation form of a transmitting device according the fourth implementation form of the first aspect, the transmitting device is configured to

update the minimum transport block size based on at least one of the maximum transport block sizes indicated in the one or more transmission grants.

The fifth implementation form offers the advantage of adapting the minimum transport block size based on the traffic characteristics or channel conditions or any other information provided in the transmission grants. In a sixth possible implementation form of a transmitting device according to the fourth or fifth implementation form of the first aspect, each one of the one or more transmission grants are associated with different consecutive transmission time intervals. The sixth implementation form provides a mechanism for adapting the minimum transport block size in the time dimension. In a seventh possible implementation form of a transmitting device according to any of the preceding implementation form of the first aspect to the first aspect as such, the minimum transport block size is less than the maximum transport block sizes.

In an eighth possible implementation form of a transmitting device according to any of the preceding implementation forms of the first aspect or to the first aspect as such, the transmitting device is configured to

receive a control message from the receiving device, wherein the control message indicates the minimum transport block size,

derive the minimum transport block size from the control message.

The control message may be received by the transmitting device before reception of one or more transmission grants.

The eighth implementation form provides the advantage of receiving the minimum transport block size along with the other configuration parameters, e.g. at the configuration/initiation of the service associated with the data packets.

In a ninth possible implementation form of a transmitting device according to the eighth implementation forms of the first aspect, the transmitting device is further configured to

receive the control message when configuring a service associated with the data packets.

The ninth implementation form offers the advantage to specify the minimum transport block size in a control message which is also associated with the configuration of the service. In one example, the control message is transmitted in the same signalling as for the initiation of the service, thereby minimizing the signalling in the system for reduced overhead.

In a tenth possible implementation form of a transmitting device according to any of the preceding implementation forms of the first aspect or to the first aspect as such, the transmitting device is configured to

assemble the transport blocks in the link layer, submit the assembled transport blocks to a layer below the link layer for transmission to the receiving device.

The link layer may e.g. be RLC layer or a corresponding layer, and the layer below the link layer may e.g. be MAC or a corresponding layer.

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

derive a minimum transport block size,

transmit a control message to a transmitting device, wherein the control message indicates the minimum transport block size,

receive assembled transport blocks comprising data packets from the transmitting device in response to the transmission of the control message.

The receiving device according to the second aspect provides a number of advantages. The receiving side typically serves several transmitting devices and grants transmission resources to the transmitting devices based on several factors, such as subscription status, channel conditions, etc. The receiving side can indicate or recommend the minimum transport block size considering these factors along with other configuration parameters. Therefore, the receiving device according to the second aspect can indicate or recommend the minimum transport block size considering configuration parameters in such a way that the transmitting device does not need to update the minimum transport block size too frequently meaning e.g. lower processing load and reduced latency.

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

derive the minimum transport block size based on a type of service associated with the data packets comprised in the assembled transport blocks.

The advantage with the first implementation form is to adapt the minimum transport block size to different service types. For example, the minimum transport block size can be larger for enhance Mobile Broadband (eMBB) compared to that for machine to machine communications, etc.

In a further possible implementation form of a receiving device according to the first implementation form of the second aspect, the type of service is any of: enhanced Mobile Broad Band, Ultra Reliable Low Latency Communications, and massive Machine Type Communications.

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

transmit the control message when configuring the service associated with the data packets comprised in the assembled transport blocks.

The second implementation form offers the advantage to specify the minimum transport block size in a control message which is also associated with the configuration of the service. In one example, the control message is transmitted in the same signalling as for the initiation of the service, thereby minimizing the signalling in the system for reduced overhead.

In a third possible implementation form of a receiving device according to any of the preceding implementation form of the second aspect or to the second aspect as such, the receiving device is configured to

transmit one or more transmission grants to the transmitting device, wherein each transmission grant grants a transmission of one or more transport blocks and indicates a maximum transport block size for such a transmission.

The third implementation form provides a dynamic updating mechanism at the transmitting device for obtaining the maximum transport block size used in the concatenation performed by the transmitting device according to the first aspect. Thereby, assembly of the transport blocks can be adapted to traffic characteristics or channel conditions or any other information provided in the transmission grants.

According to a third aspect of the invention, the above mentioned and other objectives are achieved with a method for a transmitting device, the method comprises:

deriving a minimum transport block size;

assembling transport blocks by sequentially concatenating data packets having a size smaller than the minimum transport block size into a transport block as long as a current size of the transport block is equal to or smaller than the minimum transport block size, and by inserting each data packet having a size between the minimum transport block size and a maximum transport block size into a single separate transport block without concatenation; transmitting the assembled transport blocks to a receiving device.

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

stopping concatenating data packets into a current transport block if a next to be concatenated data packet has a size larger than the remaining space in the current transport block until the minimum transport block size is reached;

concatenating the next to be concatenated data packet into a succeeding transport block.

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

deriving the remaining space based on a difference between the minimum transport block size and the current size of the transport block.

In a third possible implementation form of a method according to the first implementation form of the third aspect or to the third aspect as such, the method comprises

deriving the minimum transport block size based on a type of service associated with the data packets.

In a further possible implementation form of the method according to the third implementation forms of the third aspect, the type of service is any of: enhanced Mobile Broad Band, Ultra Reliable Low Latency Communications, and massive Machine Type Communications.

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 comprises receiving one or more transmission grants from the receiving device, wherein each transmission grant grants a transmission of one or more transport blocks and indicates the maximum transport block size for such a transmission,

deriving the maximum transport block size for the transport block based on at least one maximum transport block size indicated in the one or more transmission grants which will be used to transmit the transport block,

transmitting the assembled transport blocks to the receiving device based on the one or more transmission grants.

In a fifth possible implementation form of a method according the fourth implementation form of the third aspect, the method comprises

updating the minimum transport block size based on at least one of the maximum transport block sizes indicated in the one or more transmission grants. In a sixth possible implementation form of a method according to the fourth or fifth implementation form of the third aspect, each one of the one or more transmission grants are associated with different consecutive transmission time intervals. In a seventh possible implementation form of a method according to any of the preceding implementation form of the third aspect or to the third aspect as such, the minimum transport block size is less than the maximum transport block sizes.

In an eighth 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 comprises receiving a control message from the receiving device, wherein the control message indicates the minimum transport block size,

deriving the minimum transport block size from the control message. In a ninth possible implementation form of a method according to the eighth implementation forms of the third aspect, the method comprises

receiving the control message when configuring a service associated with the data packets. In a tenth 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 comprises assembling the transport blocks in the link layer,

submitting the assembled transport blocks to a layer below the link layer for transmission to the receiving device.

The advantages of any method according to the second aspect are the same as those for the corresponding transmitting device according to the first aspects.

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

deriving a minimum transport block size,

transmitting a control message to a transmitting device, wherein the control message indicates the minimum transport block size,

receiving assembled transport blocks comprising data packets from the transmitting device in response to the transmission of the control message. In a first possible implementation form of a method according to the fourth aspect, the method comprises

deriving the minimum transport block size based on a type of service associated with the data packets comprised in the assembled transport blocks.

In a further possible implementation form of the method according to the first implementation forms of the fourth aspect, the type of service is any of: enhanced Mobile Broad Band, Ultra Reliable Low Latency Communications, and massive Machine Type Communications. In a second possible implementation form of a method according to the first implementation form of the fourth aspect, the method comprises

transmitting the control message when configuring the service associated with the data packets comprised in the assembled transport blocks. In a third possible implementation form of a method according to any of the preceding implementation form of the fourth aspect or to the fourth aspect as such, the method comprises transmitting one or more transmission grants to the transmitting device, wherein each transmission grant grants a transmission of one or more transport blocks and indicates a maximum transport block size for such a transmission.

The advantages of any method according to the fourth aspect are the same as those for the corresponding receiving device according to the fourth aspects.

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 transmitting device according to an embodiment of the invention.

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

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

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

- Fig. 5 shows transport block assembly.

- Fig. 6 shows transport block assembly.

- Fig. 7 shows transport block assembly.

- Fig. 8 shows a transport block size update mechanism according to an embodiment of the invention.

- Fig. 9 shows a wireless communication system according to an embodiment of the invention.

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

- Fig. 11 shows signalling and transmission aspects related to embodiments of the invention.

- Fig. 12 shows the structure of a Radio Link Control (RLC) Protocol Data Unit (PDU) according to an embodiment of the invention.

Detailed Description

In a wireless communication system, such as WCDMA and LTE, data packets from a transmitting device to a receiving device are transmitted over the radio interface in so called transport blocks. In such wireless communication systems, the procedures of data transfer are classified into different protocols. The protocols are called radio access protocols or user plane protocols of radio access network or layer 2 protocols in radio access networks. For example, these protocols are Packet Data Convergence Protocol (PDCP), Radio Link Control (RLC) and Media Access Control (MAC) in WCDMA and LTE. The radio access protocols in layer 2 of the next generation wireless communication systems can be classified to higher layer protocol corresponding to PDCP, a middle layer or link layer corresponding to RLC, and a lower layer corresponding to MAC. The expressions middle layer, link layer, and RLC are used interchangeably in this disclosure. The transport blocks are assembled by the transmitting device from higher layer data packets. To achieve high data rates the transmitting device needs to efficiently assemble the data packets into suitable transport blocks.

The transmitting device can either assemble one transport block for each data packet or assemble one transport block from two or more sequential higher layer data packets. The combination of two or more data packets into one transport block is called concatenation. Without concatenation, each higher layer data packet irrespective of its size gets a link layer header which typically contains a sequence number (SN). With concatenation, two or more short data packets can share one and the same link layer header. Even though concatenation involves computing time, concatenation achieves less non-payload overhead. Concatenation can, e.g. reduce the overhead as less addressing space in the transport block is required. This is especially the case if the data packets are short. However, the time to prepare transport blocks after receiving an uplink grant may be very short in the next generation wireless communication systems which will increase the processing load on the transmitting device. Concatenation in RLC in LTE limits the possibility to pre-construct the transport blocks as the RLC PDU size is not known prior to the uplink grant. In other words, it is not clear to the transmitter how many SDU will fit into one RLC PDU before the transmitter received the uplink grant. Even though concatenation in LTE is a limiting factor to pre- construction, removing concatenation also has disadvantages as mentioned earlier. Hence, if concatenation is kept (e.g. in RLC or a corresponding layer) and implemented as described herein for data packets below a certain size, embodiments of the invention offer the twin benefits of having concatenation and the possibility to pre-construct the RLC PDUs and the transport blocks.

Therefore, embodiments of the invention provide a solution that improves the assembly of transport blocks accordingly. In this respect the assembly of transport blocks is improved by allowing the concatenation to be flexibly performed compared to conventional assembling techniques. In this respect, a minimum transport block size and a maximum transport block size are herein introduced. Further, the transmitting device can decide when and how to concatenate the data packets based on the minimum transport block size, the corresponding maximum transport block size and the size of the data packets to be transmitted to the receiving device.

In an embodiment of the invention the assembly of transport blocks is performed by a transmitting device 100, such as the transmitting device 100 shown in Fig. 1 . The transmitting device 100 comprises a processor 102 coupled to a transceiver 104. The processor 102 and the transceiver 104 are coupled to each other by communication means 108 known in the art. The transmitting device 100 further comprises an antenna 106 coupled to the transceiver 104, which means that the transmitting device 100 is configured for wireless communications in a wireless communication system. The transmitting device 1 00 is configured to derive a minimum transport block size T_Min. The transmitting device 1 00 is further configured to assemble transport blocks by sequentially concatenating data packets (DPs) having a size smaller than the minimum transport block size T_Min into a transport block TB as long as a current size of the transport block TB is equal to or smaller than the minimum transport block size T_Min, and by inserting each data packet having a size between the minimum transport block size T_Min and a maximum transport block size T_Max into a single separate transport block TB, i.e. without concatenation. The transmitting device 100 is further configured to transmit the assembled transport blocks to a receiving device 300 (see e.g. Fig. 3) which is illustrated with the dotted arrow.

Fig. 2 shows a flow chart of a corresponding method 200 which may be executed in a transmitting device 100, such as the one shown in Fig. 1 . The method 200 comprises deriving 202 a minimum transport block size T_Min. The method 200 further comprises assembling 204 transport blocks by sequentially concatenating data packets having a size smaller than the minimum transport block size T_Min into a transport block TB as long as a current size of the transport block TB is equal to or smaller than the minimum transport block size T_Min, and by inserting each data packet having a size between the minimum transport block size T_Min and a maximum transport block size T_Max into a single separate transport block TB. The method 200 further comprises transmitting 206 the assembled transport blocks to a receiving device 300.

The transmission device 100 is configured to stop concatenating data packets into the current transport block TB if a next to be concatenated data packet has a size larger than the remaining space in the current transport block TB until the minimum transport block size T_Min is reached. Hence, if with the next to be added data packet the size of the current transport block would exceed the minimum transport block size T_Min then the assembling of the current transport block is finished and the transport block is submitted to a lower layer for transmission to a receiving device. The next to be concatenated data packet is then instead assembled into a succeeding transport block TB and if its size is small enough concatenated with other succeeding data packet(s). If the size of the succeeding data packet is equal to or larger than the minimum transport block size T_Min but smaller than the maximum transport block size T_Max then the data packet will be assembled into its own transport block without any concatenation. Hence, such a resulting transport block then only comprises such long data packet and no other data packet. In other words, the transmitting device 1 00 is configured to assemble the transport blocks TBs by inserting each data packet having a size between the minimum transport block size T_Min and a maximum transport block size T_Max into a single separate transport block TB. The minimum transport block size T_Min is less than the maximum transport block size T_Max. In some embodiments the possibility may exist that the size of a data packet exceeds the maximum transport block size T_Max. In this case the transmission device 100 is configured to perform segmentation, i.e. segment the data packet over more than one transport block.

There are number of different ways how the minimum transport block size T_Min is obtained by the transmitting device 100. In one case the minimum transport block size T_Min is predetermined and available in the transmitting device 100. The minimum transport block size T_Min could e.g. be stored in a memory.

In another example the transmitting device 100 is configured to determine the minimum transport block size T_Min by considering which type of service the to be transmitted data packets are associated with. The type of service can be any of enhanced Mobile Broad Band, Ultra Reliable Low Latency Communications, and massive Machine Type Communications. Each service can then have its own minimum transport block size T_Min. As an example, when the service is initiated by an application, e.g. an ftp client, the transmitting device 100 can derive the minimum transport block size T_Min to concatenate TCP Acknowledgements (ACKs). The transmitting device 100 can set minimum transport block size T_Min so as to concatenate at least two TCP ACKs. During the service, based on the received transmission grants TGs allocated by the receiving device 300, the transmitting device 100 can update and derive the minimum transport block size T_Min based on the received transmission grants TGs. For example, the transmitting device 100 can set the minimum transport block size T_Min to be half of the value of the minimum of the maximum transport block size comprised in the transmission grants TGs for a specified number of TGs or Transmission Intervals (TTI) or a specified time. As an example, denote the maximum transport block sizes in the transmission grants TGs as T_TG1, T_TG2, ... , T_TGN. In this case the half of the value of the minimum of the maximum transport block size T_Max is equal to: 0.5 * min(T_TG1, T_TG2, ... , T_TGN). In one case each T_TG1, T_TG2, ... , T_TGN is associated with its corresponding Transmission Time Interval (TTI), see Fig. 8. In yet another case the minimum transport block size T_Min is received from the network of the wireless communication system, e.g. via a network node, by means of proper control signaling.

As already described above, the maximum transport block size T_Max can be derived by the transmitting device 100 from the transmission grants TGs received from the receiving device 300, see e.g. Fig. 8 and 1 1 . Each transmission grant TG grants a transmission of one or more transport blocks and indicates the maximum transport block size T_Max for such a transmission. The transmitting device 100 derives the maximum transport block size T_Max for the transport block TB based on at least one maximum transport block size indicated in the transmission grants TGs which will be used to transmit the transport block TB, as for example shown above. The transmitting device 100 then transmits the assembled transport blocks to the receiving device 300 based on the transmission grants TGs.

Fig. 3 shows a receiving device 300 according to an embodiment of the invention. The receiving 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 communication 308 known in the art. The receiving device 300 further comprises an antenna 306 coupled to the transceiver 304, which means that the receiving device 300 is configured for wireless communications in a wireless communication system.

The receiving device 300 is configured to derive a minimum transport block size T_Min. The receiving device 300 is configured to transmit a control message CM to a transmitting device 100. The control message CM indicates the minimum transport block size T_Min. The receiving device 300 is configured to receive assembled transport blocks comprising data packets from the transmitting device 100 in response to the transmission of the control message CM. The assembled transport blocks have been assembled by the transmitting device 100 based on the minimum transport block size T_Min indicated in the control message CM.

Fig. 4 shows a flow chart of a corresponding method 400 which may be executed in a receiving device 300, such as the one shown in Fig. 3. The method 400 comprises deriving 402 a minimum transport block size T_Min. The method 400 further comprises transmitting 404 a control message CM to a transmitting device 100. The control message CM indicates the minimum transport block size T_Min. The method 400 further comprises receiving 406 transport blocks TBs comprising data packets from the transmitting device 1 00 in response to the transmission of the control message CM. There are number of different ways how the minimum transport block size T_Min is obtained by the receiving device 300. In one case the minimum transport block size T_Min is predetermined and available in the receiving device 300, e.g. stored in a memory. In another example the receiving device 300 is configured to determine the minimum transport block size T_Min by considering which type of service the data packets are associated with. The type of service can be any of enhanced Mobile Broad Band, Ultra Reliable Low Latency Communications, and massive Machine Type Communications.

The receiving device 300 may derive the minimum transport block size T_Min during the configuration of the service associated with the data packets to be transmitted by the transmitting device 100. To initiate the service, the transmitting device 100 requests the service by sending a control message requesting the service to the receiving device 300. For example, in LTE the transmitting device sends a "RRC Connection Request" message to the receiving device 300 in this respect. For the next generation wireless system, the control message can be of similar type. The receiving device 300 will then inform the transmitting device 100 of the derived minimum transport block size T_Min by transmitting the earlier described control message CM. In this scenario, the receiving device 300 transmits the control message CM to the transmitting device 1 00 when configuring the service associated with the data packets comprised in the assembled transport blocks. The transmitting device 100 receives the control message CM and derives the minimum transport block size T_Min from the control message CM during the configuration of the service associated with the data packets.

The minimum transport block size T_Min is not necessarily static during the service execution. Instead, the minimum transport block size T_Min can be dynamically updated by the transmitting device 1 00 based on transmission grants TGs from the receiving device 300. For example, if the maximum transport block size T_Max of the transmission grants TGs allocated by the receiving device 300 is higher than the minimum transport block size T_Min, the transmitting device 100 can increase the minimum transport block size T_Min. A couple of solutions to update T_Min are described below.

In one solution, the minimum transport block size T_Min can be half the size of the minimum of the maximum transport block size comprised in the transmission grants TGs received so far or received in the last N number of TTIs (wherein N could be predefined or flexibly adapted) by the transmitting device 100 as previously described. In another solution, the transmitting device 100 can use an exponential average of the maximum transport block size comprised in the transmission grants TGs to update the minimum transport block size T_Min. Further, the minimum transport block size T_Min can be decreased if the maximum transport block size comprised in the transmission grants TGs received by the transmitting device 1 00 are smaller than the minimum transport block size T_Min. Also other solutions are possible. Generally, the minimum transport block size T_Min is updated based on a function of one or more transmission grants TGs. Examples of functions have been previously described, such as a linear function or exponential average.

The transmitting device 100 may assemble the transport blocks in the link layer and submit the assembled transport blocks to a layer below the link layer for transmission to the receiving device 300. The link layer functions in the transmitting device 1 00 can be implemented using the RLC protocol, which is a link layer protocol used in e.g. LTE and WCDMA. However, the link layer functions can also be implemented using any other known corresponding protocols or future protocols. In the LTE example, the RLC protocol receives data packets from higher layers which are assembled into RLC PDUs. The present exemplary RLC protocol can dynamically decide whether concatenation of the higher layer packets should be performed or not.

Figs. 5-7 illustrates the assembly of RLC PDUs by the RLC protocol in three different exemplary scenarios in a LTE or WCDMA system context. The higher layer data packets of sizes X1 , X2,..., X6 bytes are short data packets, e.g. for TCP signaling traffic. The higher layer data packets of sizes Y1 and Y2 bytes are e.g. TCP data traffic of a few hundred bytes each. The higher layer data packets of sizes Z1 and Z2 bytes are very long packets, also known as jumbo packets in the art. Further, the RLC PDUs comprises sequence number SN (numbered from k) and the length indicator (LI) as shown in Figs. 5-7.

In Fig. 5 all the higher layer packets are short data packets of sizes X1 , X2,..., X6 bytes. The RLC protocol according to an embodiment therefore concatenates the higher layer data packets of sizes X1 , X2,..., X6 into one RLC PDU as long as the current RLC PDU size stay smaller than or equal to the minimum transport block size T_Min. In the example of Fig. 5, the next to be concatenated short data packet of size X4 did not fit into the current RLC PDU with SN k (shown on the left side of Fig. 5) as otherwise the minimum transport block size T_Min would be exceeded. Hence, the data packet with size X4 and the following data packets are assembled into the next RLC PDU with SN k+1 . In Fig. 6 a mixture of short and long higher layer data packets are to be assembled in transport blocks. It should be noted in Fig. 6 that the minimum transport block size T_Min is different for different RLC PDUs implying concatenation flexibility. The three first higher layer data packets of sizes X1 , X2 and X3 are concatenated into the first RLC PDU. The next higher layer data packet of size Y1 is not concatenated with the following higher layer data packet of size Y2 as this concatenation would result in a RLC PDU exceeding the minimum transport block size T_Min. The higher layer data packet of size Y1 is therefore assembled in a single separate RLC PDU since the size of data packet Y1 is less than the maximum transport block size T_Max. The higher layer data packet of size Y2 is concatenated with the following shorter higher layer data packet of size X4 into the third RLC PDU.

In Fig. 7, the RLC protocol does not apply concatenation at all as the higher layer data packet of sizes Z1 , Z2 are larger than the minimum transport block size T_Min but smaller than the maximum transport block size T_Max. In this case, such large higher layer data packets are inserted into a single RLC PDU without concatenation. However, if the size of the higher layer data packet is even larger than the maximum transport block size T_Max segmentation of the data packets would be applied so as to fit them into a given RLC PDU.

Fig. 8 illustrates dynamic adaption of the minimum transport block size T_Min in uplink example at the transmitting device 100.

At step I) the minimum transport block size T_Min is set to the value T_Min = K by the receiving device 300 or by its associated network at the service configuration for data packets to be transmitted. Further, a control message CM comprising the set minimum transport block size T_Min is transmitted from the receiving device 300 to the transmitting device 100 at step I).

During step II) the receiving device 300 transmit a control message CM comprising the minimum transport block size T_Min = K to the transmitting device 1 00. Also, one or more transmission grants TGs are transmitted by the receiving device 300 to the transmitting device 100 during step I I). Each transmission grant TG grants a transmission of one or more transport blocks and indicates a maximum transport block size for such a transmission. The maximum transport block size is larger than the minimum transport block size T_Min = K. In addition, each one of the transmission grants TGs can be associated with different consecutive TTIs.

At step I I) the transmitting device 100 receives the transmission grants TGs and derives the maximum transport block size T_Max based on at least one of the maximum transport block sizes indicated or comprised in the transmission grants TGs. Further, an updating mechanism for deriving the minimum transport block size T_Min is also provided by considering the maximum transport block sizes in the transmission grants TGs according to any of the previously described solutions. Hence, the value of the minimum transport block size T_Min is adapted to the values of the maximum transport block sizes comprised in the transmission grants TGs. Therefore, the value of the minimum transport block size T_Min can increased or decreased accordingly.

Finally, the transmitting device 100 transmits the assembled transport blocks TBs to the receiving device 300 based on the one or more transmission grants TGs. This is however not shown in Fig. 8. Fig. 9 shows a wireless communication system 500 comprising a transmitting device 100 and a receiving device 300 according to embodiments of the invention. In this example the transmitting device 100 is part of a client device 600 and the receiving device 300 is part of a network node 700. Fig. 9 shows an uplink scenario, where data packets are transmitted in transport blocks TBs from the client device 600 to the network node 700.

Embodiments of the invention can also be used in a downlink scenario as shown in Fig. 10. Herein, the transport blocks TBs are transmitted from the network node 700, which therefore comprises the transmitting device 100. The transport blocks TBs are received by the client device 600 which comprises the receiving device 300.

Fig. 11 illustrates different signaling and transmission aspects according to embodiments of the invention. The transmitting device 1 00 transmits data packets to the receiving device 300 in assembled transport blocks TBs as previously described. The receiving device 300 transmits one or more control messages CMs to the transmitting device 100 which derives the minimum transport block size T_Min from the one or more control messages CMs. Based on the minimum transport block size T_Min, in the one or more control messages CMs, the transmitting device 100 assembles TBs and transmit these TBs to the receiving device 300. Further, the receiving device 300 transmits one or more TGs to the transmitting device 1 00 which updates the value of the maximum transport block size T_Max based on the maximum transport block sizes indicated in the one or more TGs. The transmitting device 100 assembles TBs based on the updated maximum transport block size T_Max and transmit these TBs to the receiving device 300.

An exemplary structure of the RLC PDU according to an embodiment of the invention is shown in Fig. 1 2. A RLC PDU assembled from two higher layer packets is illustrated with the two dashed arrows. The D/C field indicates if the RLC PDU is a RLC data PDU or a RLC control PDU. Further, the SN field which is the sequence number added by the RLC protocol to each assembled RLC PDU. The first E field (i.e. the E field following D/C field or preceding the SN field in Fig. 12) indicates if there are E and length indicator fields following the SN. The E fields further on in the PDU structure denote if there are more E field and length indicator fields. As an example, in Fig. 12, two higher layer data packets are concatenated. The first E field is set to 1 indicating there are E field and length indicator fields following the SN. The second E field is also set to 1 indicating there are E field and length indicator fields following the current length indicator field. The third E field is set to 0 indicating there are no more E fields and length indicator fields after the current length indicator field. LI1 corresponds to the size of the higher layer data packet 1 and LI2 corresponds to the size of the higher layer data packet 2.

The aforementioned client device also 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. The aforementioned network node also 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. 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 transmitting device 100 and the receiving 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 of the transmitting device 100 and the processor 302 of the receiving 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.

Claims

1 . A transmitting device (100) for a wireless communication system (500), the transmitting device (100) being configured to

derive a minimum transport block size (T_Min) ;

assemble transport blocks by sequentially concatenating data packets having a size smaller than the minimum transport block size (T_Min) into a transport block (TB) as long as a current size of the transport block (TB) is equal to or smaller than the minimum transport block size (T_Min), and by inserting each data packet having a size between the minimum transport block size (T_Min) and a maximum transport block size (T_Max) into a single separate transport block (TB) ;

transmit the assembled transport blocks to a receiving device (300).

2. The transmitting device (1 00) according to claim 1 , configured to

stop concatenating data packets into a current transport block (TB) if a next to be concatenated data packet has a size larger than the remaining space in the current transport block (TB) until the minimum transport block size is reached;

concatenate the next to be concatenated data packet into a succeeding transport block (TB).

3. The transmitting device (1 00) according to claim 1 or 2, configured to

derive the minimum transport block size (T_Min) based on a type of service associated with the data packets.

4. The transmitting device (1 00) according to any of the preceding claims, configured to

receive one or more transmission grants (TGs) from the receiving device (300), wherein each transmission grant (TG) grants a transmission of one or more transport blocks and indicates the maximum transport block size for such a transmission,

derive the maximum transport block size (T_Max) for the transport block (TB) based on at least one maximum transport block size indicated in the one or more transmission grants (TGs) which will be used to transmit the transport block (TB),

transmit the assembled transport blocks to the receiving device (300) based on the one or more transmission grants (TGs).

5. The transmitting device (100) according to claim 4, configured to

update the minimum transport block size (T_Min) based on at least one of the maximum transport block sizes indicated in the one or more transmission grants (TGs).

6. The transmitting device (100) according to claim 4 or 5, wherein each one of the one or more transmission grants (TGs) are associated with different consecutive transmission time intervals.

7. The transmitting device (100) according to any of the preceding claims, wherein the minimum transport block size (T_Min) is less than the maximum transport block sizes (T_Max).

8. The transmitting device (100) according to any of the preceding claims, configured to

receive a control message (CM) from the receiving device (300), wherein the control message (CM) indicates the minimum transport block size (T_Min),

derive the minimum transport block size (T_Min) from the control message (CM).

9. The transmitting device (100) according to claim 8, configured to

receive the control message (CM) when configuring a service associated with the data packets.

10. The transmitting device (100) according to any of the preceding claims, configured to assemble the transport blocks in the link layer

submit the assembled transport blocks to a layer below the link layer for transmission to the receiving device (300).

1 1 . A receiving device (300) for a wireless communication system (500), the receiving device (300) being configured to

derive a minimum transport block size (T_Min),

transmit a control message (CM) to a transmitting device (100), wherein the control message (CM) indicates the minimum transport block size (T_Min),

receive assembled transport blocks comprising data packets from the transmitting device (100) in response to the transmission of the control message (CM).

12. The receiving device (300) according to claim 1 1 , configured to

derive the minimum transport block size (T_Min) based on a type of service associated with the data packets comprised in the assembled transport blocks.

13. The receiving device (300) according to claim 12, configured to

transmit the control message (CM) when configuring the service associated with the data packets comprised in the assembled transport blocks.

14. The receiving device (300) according to any of claims 1 1 to 13, configured to transmit one or more transmission grants (TGs) to the transmitting device (300), wherein each transmission grant (TG) grants a transmission of one or more transport blocks and indicates a maximum transport block size for such a transmission.

15. The transmitting device (100) according to claim 3 or any claim referenced back to claim 3 or the receiving device (300) according to claim 12 or any claim referenced back to claim 1 2, wherein the type of service is any of: enhanced Mobile Broad Band, Ultra Reliable Low Latency Communications, and massive Machine Type Communications.

16. Method for a transmitting device (100), the method (200) comprising:

deriving (202) a minimum transport block size (T_Min) ;

assembling (204) transport blocks by sequentially concatenating data packets having a size smaller than the minimum transport block size (T_Min) into a transport block (TB) as long as a current size of the transport block (TB) is equal to or smaller than the minimum transport block size (T_Min) , and by inserting each data packet having a size between the minimum transport block size (T_Min) and a maximum transport block size (T_Max) into a single separate transport block (TB);

transmitting (206) the assembled transport blocks to a receiving device (300).

17. Method for a receiving device (300), the method (400) comprising:

deriving (402) a minimum transport block size (T_Min),

transmitting (404) a control message (CM) to a transmitting device (100), wherein the control message (CM) indicates the minimum transport block size (T_Min) ,

receiving (406) transport blocks comprising data packets from the transmitting device (100) in response to the transmission of the control message (CM).

18. A computer program with a program code for performing a method according to claim 1 6 or 17 when the computer program runs on a computer.