CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No. PCT/CN2017/099510 filed Aug. 29, 2017.

FIELD OF THE INVENTION

The non-limiting and exemplary embodiments of the present disclosure generally relate to the field of wireless communication techniques, and more particularly relate to a method, network device, and apparatus for transmitting a preemption indication and a method, terminal device, and apparatus for receiving a preemption indication.

BACKGROUND OF THE INVENTION

New radio access system, which is also called as NR system or NR network, is the next generation communication system. In Radio Access Network (RAN) #71 meeting for the third generation Partnership Project (3GPP) working group, study of the NR system was approved. The NR system will consider frequency ranging up to 100 Ghz with an object of a single technical framework addressing all usage scenarios, requirements and deployment scenarios defined in Technical Report TR 38.913, which includes requirements such as enhanced mobile broadband, massive machine-type communications, and ultra-reliable and low latency communications.

In the wireless communication system, there can be different types of transmissions, such as Ultra-Reliable Low Latency Communications (URLLC) transmission and Enhance Mobile Broadband (eMBB) transmission. When assigned resources of a type of transmission have been partially prompted by another type of transmission, a preemption indicator is usually required to indicate the preempted resources.

In 3GPP RAN 1 #88 meeting, the following agreements were made on the preemption indicator:Indication can be dynamically signaled to user equipment (UE), whose assigned downlink (DL) resources have been partially preempted by another DL transmission, to increase the likelihood of successful demodulation and decoding of Transport Blocks (TBs) transmitted within the above mentioned assigned resource.The indication may be used to increase the likelihood of successful demodulation and decoding of the TB based on the preempted transmission and/or subsequent (re)-transmissions of the same TB.

IN RANI #89 meeting, it was further agreed that when the preemption indication is configured, it informs UE(s) which DL physical resources has been preempted and the preemption indication is transmitted using a Physical Downlink Control Channel (PDCCH).

For illustration purposes,FIG. 1illustrates an example transmission of URLLC/eMBB multiplexing. As illustrated, resources illustrated by blocks with slashes are used for a first transmission (like eMBB transmission) while a part of these resources are preempted by another transmission (like URLLC transmission) illustrated by blocks with dots. In such a case, an indication can be signaled to a terminal device which is performing the first transmission to inform the preempted resources.

Usually, there are two options to transmit the Group Common—Downlink Control Indication (GC-DCI) for the preemption indication. One option is to configure only one GC-DCI which contains information on all URLLCs. In other words, all terminal devices in a group monitor the same GC-DCI. However, it might require a rather large payload of GC-DCI, and the URCCLs are un-predictable since it is hard to know how many URLLCs will occur. In addition, as illustrated by the bold blocks inFIG. 2, part4and part2are overlapped with each other in the frequency domain but they will be indicated separately, which causes repeated indications. Moreover, this solution also is involved in an issue on unnecessary indication. As an example, part1only relates to eMBB UE1,2and3, and in fact, eMBB UE4,5does not need to know information on part1at all; however, in such a solution, a preemption of part1will still be informed to eMBB UE4and5.

Another option is to configure a plurality of GC-DCIs. However, due to the un-predictability, it is required to further indicate the number of GC-DCIs, which means an extra signaling overhead. In addition, UE needs to monitor all the GC-DCIs since it does not know whether to monitor GC-DCI or which GC-DCI to monitor. Thus, the UE might make substantial blind-decoding attempts. Moreover, issues on the repeated indication and unnecessary indication still exist in this option.

In 3GPP technical document R1-1712976, it is proposed to associate different GC-DCIs with different reference regions. As illustrated inFIG. 3A, there are two reference regions, i.e., reference region1and reference region2; GC-DCI1is associated with reference region1which spans from frequency f0to f1and from time t0to t1; GC-DCI2is associated with reference region2which spans from frequency f2to f3and from time t0to t2. GC-DCI1can be used to indicate any resource preemption within reference region1; GC-DCI2can be used to indicate any resource preemption within reference region2. These reference regions may be configurable, e.g. by RRC signalling, or configured dynamically if necessary. With this solution, the UE could know which GC-DCI to monitor based on its allocated resource.

However, in this solution, these reference regions are predefined for DCI monitoring, but the second transmission like URLLC may happen at any frequency band and any time position and thus all UE within a reference region shall monitor and decode GC-DCIs associated with the reference region. For example, all UE allocated in the second reference region need to monitor and decode GC-DCI2. In addition, it is also hard to decide the size of GC-DCI2and the overhead might be very large due to the unpredictability of the URLLC. At the same time, the solution also has issues on repeated indication and unnecessary indication. Moreover, the URLLC might go beyond a reference region. As illustrated inFIG. 3Bby the black blocks, both of URLLC transmissions extend beyond reference region2(covered with dots) and thus require further preemption indications.

In 3GPP technical document R1-1710123, there was also proposed another solution wherein the available time/frequency resources are divided into two regions, i.e., one region where a possible resource preemption of URRLC transmission can happen and the other region where preemption URLLC traffic will not be scheduled, as illustrated inFIG. 4. When UE is in the shared zone, the UE could know this and will monitor possible preemption indications. However, there are still similar issues to those two possible options as mentioned above.

In 3GPP technical document R1-1712668, it was proposed that the scheduling unit of URLLC should start at predefined eMBB symbols within eMBB numerology slot, as illustrated inFIG. 5. In this way, both the DCI monitoring and overhead of the preemption indication could be reduced at the expense of a slightly increased latency of the URLLC traffic.

However, these current solutions cannot meet requirements of efficient preemption indications and thus there is a need for improved preemption indication solution in the art.

SUMMARY OF THE INVENTION

To this end, in the present disclosure, there is provided an improved solution of preemption indication to mitigate or at least alleviate at least part of the issues in the prior art.

According to a first aspect of the present disclosure, there is provided a method of transmitting a preemption indication. The method may comprise transmitting a preemption indication to a terminal device, wherein the preemption indication indicates information on a portion of resources allocated to a first transmission which is preempted by a second transmission, and wherein the preemption indication is associated with information on structure of the current slot.

According to a second aspect of the present disclosure, there is provided method of receiving a preemption indication. The method may comprise monitoring a preemption indication from a network device, wherein the preemption indication indicates information on a portion of resources allocated to a first transmission which is preempted by a second transmission; and decoding the preemption indication based on information on structure of the current slot to obtain the information on the portion of resources.

According to a third aspect of the present disclosure, there is provided a network device. The network device may comprise a transceiver, the transceiver being configured to transmit a preemption indication to a terminal device, wherein the preemption indication indicates information on a portion of resources allocated to a first transmission which is preempted by a second transmission, and wherein the preemption indication is associated with information on structure of the current slot.

According to a fourth aspect of the present disclosure, there is provided a terminal device. The terminal device may comprise a processor, the processor being configured to: monitor a preemption indication from a network device, wherein the preemption indication indicates information on a portion of resources allocated to a first transmission which is preempted by a second transmission, and the processor being further configured to decode the preemption indication based on information on structure of the current slot to obtain the information on the portion of resources.

According to a fifth aspect of the present disclosure, there is provided a computer-readable storage media with computer program codes embodied thereon, the computer program codes being configured to, when executed, cause an apparatus to perform actions in the method according to any embodiment in the first aspect.

According to a sixth aspect of the present disclosure, there is provided a computer-readable storage media with computer program codes embodied thereon, the computer program codes being configured to, when executed, cause an apparatus to perform actions in the method according to any embodiment in the second aspect.

According to a seventh aspect of the present disclosure, there is provided a computer program product comprising a computer-readable storage media according to the fifth aspect.

According to an eighth aspect of the present disclosure, there is provided a computer program product comprising a computer-readable storage media according to the sixth aspect.

In embodiments of the present disclosure, by means of information on structure of a subframe, the indication monitoring and overhead for the preemption indication can be reduced remarkably, thereby providing a much more efficient preemption indication solution.

