CN111713055A

CN111713055A - Apparatus and method for transmitting data packets in a communication network

Info

Publication number: CN111713055A
Application number: CN201880089026.4A
Authority: CN
Inventors: 卡斯柯杨·加尼森; 阿里·拉马丹·阿里; 桑迪普·甘卡克黑卡尔; 阿民·玛瑞夫; 约瑟夫·艾辛格; 吕永霞
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2018-02-12
Filing date: 2018-02-12
Publication date: 2020-09-25
Also published as: WO2019154522A1

Abstract

Apparatus and method for transmitting data packets in a communication network. The invention relates to a transmitter (601) for transmitting data packets to a receiver (631), in particular according to a hybrid automatic repeat request (HARQ) scheme or a blind repetition scheme. The transmitter (601) comprises a communication interface (603) and a processor (605), the communication interface (603) being configured to transmit a data packet, the processor (605) being configured to determine a first transmission multiplexing scheme for transmitting the data packet in a first transmission and to determine a second transmission multiplexing scheme for transmitting the data packet in a second transmission, wherein the first transmission multiplexing scheme is associated with a higher block error rate than the second transmission multiplexing scheme, and the first transmission is separated in time from the second transmission.

Description

Apparatus and method for transmitting data packets in a communication network

Technical Field

The present invention relates generally to mobile communications. More particularly, the present invention relates to a transmitter and a receiver and a corresponding method for transmitting data packets in a mobile communication network.

Background

Ultra-high-reliable low-latency communication (urlllc) is one of the key requirements for 5G New Radio (NR) technology for vehicle communication, industrial automation, etc., where transmission of small data requires low latency of 1ms and a relatively high reliability of 99.999%, as shown in the table of fig. 1.

Spectrally inefficient low modulation and coding rates are critical to meet challenging urlllc reliability requirements that ultimately require more bandwidth, thus limiting the urlllc connections of User Equipment (UE) per cell. Due to the increased queuing delay, meeting the uRLLC requirements at high cell load is a challenging task, where the total delay includes the queuing delay, the transmission time, the processing time of the receiver, and N-1 times the round trip time of HARQ (hybrid automatic repeat request), where N is the total number of transmissions.

In addition, as shown in fig. 2, the 5G NR should be designed to support multiple services simultaneously, and take into account Key Performance Indicators (KPIs) of various vertical industries.

In the current standardization of the 5G NRRAN1, many methods for coexistence of enhanced mobile broadband (eMBB) and urrllc have been studied: in a first method of dynamic resource sharing of urrllc and eMBB, it is agreed to schedule resources for eMBB and urrllc, respectively, on non-overlapping time/frequency resources. Thus, the implementation of the dynamic resource sharing scheme is very similar to the existing user scheduling method, which relies mainly on the base station scheduler.

In a second semi-static partitioning method of eMBB and urrllc resources, consideration is also given to where in time or frequency the resources are partitioned by RRC signaling based on load conditions.

In a third approach, the preemption-based approach is considered in the case as shown in fig. 3, in which case micro-slot based urrllc transmission 303 may occur when resources have been scheduled for ongoing downlink eMBB data transmission 301. In the preemption method, once the urrllc packet arrives, a portion of the resources allocated to the eMBB data will be punctured and reallocated to the UE for urrllc transmission. A post-indication message regarding the affected resources is sent to the eMBB UE to avoid soft buffer pollution to HARQ, and subsequent transmissions from a next generation base station (next generation node B, gNB) immediately schedule the affected resources without waiting for feedback.

The main focus of the current standardization is how the eMBB UE reads the preemption indication to avoid soft buffer pollution for HARQ transmissions. However, the main drawback of the preemption scheme is that the reliability of the eMBB may be affected and recovering the retransmission opportunities needed for the preemption impact will affect the overall spectrum efficiency. After the urrllc transmission is complete, the eMBB transmission may resume. In this case, the latency of the eMBB transmission will increase.

In the 5G NR standard, various options are proposed for the urrllc transmission, e.g. a single urrllc transmission, to achieve strict reliability and latency without attempting HARQ transmissions, which requires higher bandwidth. The second approach is based on repeated urrllc transmissions without feedback Acknowledgements (ACKs) or Negative Acknowledgements (NACKs) for L (L >1) times to achieve the required block error rate (BLER) target, where subsequent repetitions for the same Transport Block (TB) can be dynamically altered, e.g. transmit power or resource allocation. For details on this method, see the "reliability enhancement for unlicensed transport" published at RAN1-AH-1801 conference.

A third method based on HARQ based adaptive transmission with multiple Channel Quality Indicator (CQI) reports is based on flexible BLER target configuration. Therefore, for the initial transmission procedure, a relaxed Modulation and Coding Scheme (MCS) with a BLER of 10% is selected, and data is retransmitted using a stricter BLER target and a strict or lower MCS scheme. More detailed information on the third approach can be found in the "MCS/CQI design for uRLLC transmission" published in RAN1-AH-1801 conference.

Depending on the application, the reliability required for the uRLLC service can be as high as 99.999% within a certain delay range. Due to the low code rate used, the resources required to transmit the uRLLC packets are typically higher than the resources required for the eMBB in order to meet the above requirements.

The non-orthogonal transmission scheme may be applicable to both intra-UE multiplexing and/or inter-UE multiplexing of eMBB and urrllc, according to which the same time/frequency resources are reused. Several non-orthogonal schemes have been proposed, which mainly combine code-based multiplexing, power-based multiplexing on top of orthogonal scheduling methods. Such transmission schemes include, for example, superposition transmission based on multi-user superposition technology (MUST), Sparse Code Multiple Access (SCMA), Resource Spread Multiple Access (RSMA), and so on. More detailed information on non-orthogonal transmission schemes can be found in the "discussion on UL multiplexing for grant based eMBB and URLLC" published at RAN1-NR #2 conference and "chinese communication" volume 13, 2016 complimenting the "5G non-orthogonal multiple access analysis" in phase 2.

For the case of multiplexing within the UE, when the urrllc transmission is triggered, the user has an ongoing eMBB transmission, and the user may reuse the eMBB resources for the urgent urrllc transmission. If the eBB resources are reused for the uRLLC transmission, part of the eBB and uRLLC resources will overlap in both time and frequency domains simultaneously by non-orthogonal multiple access (NOMA) technique, a superposition technique, to provide the required spectral efficiency. The reliability of NOMA depends on the high signal to noise (SNR) channel conditions, the algorithm complexity of the receiver, etc.

On the other hand, in the case of a rich multipath environment, spatial multiplexing may be an option to solve the eMBB and urrllc coexistence problem by mapping the eMBB and urrllc services into different MIMO layers. In the coexistence area of the eMBB and urrllc, the eMBB service may be transmitted using a default transmitter scheme (e.g., SISO or 2x2MIMO) configured by the base station. As shown in fig. 4, once the urlllc scattered data arrives, additional MIMO layers are added to spatially multiplex the urlllc data with the eMBB data.

Spatial multiplexing is particularly well suited for use in situations such as indoor industrial automation, or vehicle-to-vehicle (V2V) communications, where the benefits of spatial multiplexing in rich multipath environments can be realized. The widely spaced antennas placed on the vehicle make the degree of coherence between these antennas very low, which is critical to reduce interference to the receiver. Applicable scenarios may be downlink communication and sidelink communication. Spatial diversity techniques may also be applied in conjunction with spatial multiplexing to enhance the overall signal-to-noise ratio, while the reliability performance of the uRLLC service may be further enhanced by closed-loop MIMO precoding techniques with weighted eigenvectors for the uRLLC transmission.

Although non-orthogonal multiplexing transmission schemes and spatial multiplexing transmission schemes provide the high spectral efficiency required for coexistence of uRLLC and eMBB, meeting reliability requirements of uRLLC over a particular range of time delays remains an issue. For intra-UE multiplexing, the channel conditions of urrllc/eMBB remain the same and the limitation of the channel capacity of the same UE also applies, which also remains the same in the initial phase for any other NOMA scheme.

The conventional adaptive HARQ mechanism of LTE aims at a BLER of 10% for initial transmission, and retransmissions need to correct errors in link adaptation due to channel defects. As shown in fig. 5, the allocated resource blocks are allowed to be changed along with a Redundancy Version (RV). However, radio resources according to the conventional adaptive HARQ mechanism are not effectively utilized. Therefore, efficiently providing resources and meeting reliability requirements for uRLLC services in the case of coexistence of uRLLC and eMBB is a major challenge for 5G NR design.

In view of the above, there is a need for improved apparatus and methods to allow for efficient and reliable transmission of data packets in a mobile communication network.

Disclosure of Invention

It is an object of the present invention to provide improved apparatus and methods enabling efficient and/or reliable transmission of data in a mobile communications network.

The foregoing and other objects are achieved by the subject matter of the independent claims. Other embodiments will be apparent from the dependent claims, the description and the drawings.

In general, the present invention relates to a transmitter and a receiver and a corresponding method of transmitting data packets in a mobile communication network. More specifically, a transmitter and receiver according to embodiments may use a resource-efficient type of transmission technique to improve overall spectral efficiency and increase average cell throughput for coexistence of eMBB data and urrllc data in a 5G mobile network.

In addition, the embodiments of the present disclosure simultaneously apply HARQ-less transmission, which is a dynamic transmission multiplexing scheme based on blind repetition, and/or HARQ-based adaptive transmission, and explore the coexistence effect of urrllc and eMBB under different multiplexing schemes and different reliability targets according to HARQ-based adaptive transmission. Therefore, embodiments of the present invention may achieve high urrllc reliability in a resource efficient manner within the HARQ latency range by avoiding over-provisioning of resources and increasing the system capacity of the urrllc users.

More particularly, according to a first aspect, the present invention relates to a transmitter for transmitting data packets to a receiver, in particular according to a hybrid automatic repeat request (HARQ) scheme or a blind repetition scheme, wherein the transmitter comprises a communication interface for transmitting the data packets and a processor for determining a first transmission multiplexing scheme for transmitting the data packets in a first transmission and for determining a second transmission multiplexing scheme for transmitting the data packets in a second transmission, wherein the multiplexing scheme comprises a multiplexing of at least two different services and the first transmission multiplexing scheme is associated with a block error rate that is higher than the second transmission multiplexing scheme, and wherein the first transmission is separated in time from the second transmission. The at least two different services include an eMBB transport block and a urrllc transport block with different reliability targets.

Further, the multiplexing scheme may be a scheme of multiplexing at least two orthogonal signals or non-orthogonal signals, wherein the non-orthogonal multiplexing includes spatial multiplexing or non-orthogonal multiple access multiplexing (nomammultiplexing). Other multiplexing schemes include methods based on eMBB preemption or dynamic scheduling, for example.

Thus, an improved transmitter is provided which allows to send data packets to a receiver in an efficient and reliable manner.

In another possible implementation of the first aspect, the communication interface is configured to receive a retransmission request after sending the data packet in the first transmission, wherein the request is for retransmitting the data packet; the processor is configured to determine a second multiplexing scheme based on the reliability target after receiving the retransmission request.

In this case, the second transmission is a retransmission requested by the retransmission request.

In another possible implementation of the first aspect, the processor is configured to determine the second multiplexing scheme after expiration of a predetermined time interval after determining the first transmission multiplexing scheme, and/or the communication interface is configured to retransmit the data packet in the second transmission after expiration of the predetermined time interval after the first transmission.

The predetermined time interval may be a parameter from the autonomous HARQ transmission scheme.

In another possible implementation of the first aspect, the data packet comprises a first data packet portion and a second data packet portion, wherein the first data packet portion of the data packet requires higher reliability and/or lower latency than the second data packet portion.

In another possible implementation of the first aspect, the first data packet part is associated with a data transmission service, in particular with a uRLLC service, wherein the data transmission service may further comprise requested transport blocks from the MAC layer, and the processor is configured to determine a respective transmission multiplexing scheme that satisfies a block error rate requirement associated with the data transmission service.

Therefore, a suitable transmission method may be selected based on the reliability requirements of the data transmission service (particularly the uRLLC service) to meet the requirements of the uRLLC data transmission.

In another possible implementation of the first aspect, the second data packet part is associated with another data transmission service, in particular an eMBB service for data transmission.

In another possible implementation of the first aspect, the first transmission multiplexing scheme is associated with transmissions according to the first transmission scheme and the second transmission multiplexing scheme is associated with transmissions according to the second transmission scheme.

In another possible implementation of the first aspect, the first transmission scheme and the second transmission scheme comprise at least one of the following schemes: superimposing the first packet portion with a second packet portion, in particular, for example, a non-orthogonal multiple access (NOMA) based transmission method, and/or spatial multiplexing, coding scheme, modulation, preemption, puncturing, or scheduling, wherein the second transmission scheme is different from the first transmission scheme.

In another possible implementation of the first aspect, the first transmission multiplexing scheme provides a higher spectral efficiency than the second transmission multiplexing scheme.

The processor of the transmitter may first utilize a superposition of urlllc and eMBB for initial transmission (e.g., by using NOMA or spatial multiplexing) to save resources, and then may apply a robust transmission method, such as an orthogonal frequency-division multiplexing (OFDM) scheme, to ensure higher reliability during retransmission. Therefore, flexibility and reliability targets are explored together with transmission multiplexing schemes such as NOMA, spatial multiplexing, or orthogonal scheduling methods.

In another possible implementation of the first aspect, the processor is further configured to determine a respective transmission multiplexing scheme for retransmitting the data packets based on channel conditions between the transmitter and the receiver.

In a further possible implementation of the first aspect, the communication interface is further configured to signal the respective transmission multiplexing scheme to the receiver, in particular in control information, wherein the respective transmission multiplexing scheme comprises information indicating the respective transmission scheme.

In another possible implementation of the first aspect, the communication interface is further configured to transmit the data packet to the receiver using a predetermined transmit multiplexing scheme.

In another possible implementation of the first aspect, the communication interface is further configured to transmit a reconfiguration message to the receiver, wherein the reconfiguration message indicates one or more predetermined sets of transmission multiplexing schemes, the transmission multiplexing schemes being associated with redundancy versions and/or transmission numbers; signaling the one or more predetermined sets to a receiver in the reconfiguration message, wherein the control information performs dynamic activation of one of the one or more predetermined sets.

In another possible implementation of the first aspect, the communication interface of the transmitter is further configured to transmit a reconfiguration message to the receiver, wherein the reconfiguration message indicates a change from transmitting data packets using a predetermined transmission multiplexing scheme to transmitting data packets using a corresponding transmission multiplexing scheme; and signaling the respective transmission multiplexing scheme to the receiver, in particular by means of control information, wherein the respective transmission multiplexing scheme comprises information indicating the respective transmission scheme.

According to a second aspect, the present invention relates to a method of transmitting data packets to a receiver, in particular according to a hybrid automatic repeat request (HARQ) scheme or a blind repetition scheme. The method comprises the following steps: determining a first transmit multiplexer for transmitting data packets in a first transmission; transmitting the data packet in a first transmission using a first transmission multiplexing scheme; determining a second transmit multiplexing scheme for transmitting the data packets in a second transmission, wherein a block error rate associated with the first transmit multiplexing scheme is higher than a block error rate associated with the second transmit multiplexing scheme; and transmitting the data packet in a second transmission using a second transmit multiplexing scheme, wherein the first transmission and the second transmission are separated in time.

The above method may be implemented using a transmitter according to the first aspect.

Thus, an improved method is provided, allowing to transmit data packets to a receiver in an efficient and reliable way.

According to a third aspect, the present invention relates to a receiver for receiving data packets from a transmitter, in particular data packets transmitted according to a hybrid automatic repeat request (HARQ) scheme or a blind repetition scheme. The receiver includes a communication interface and a processor. The communication interface is configured to receive data packets according to a first transmission multiplexing scheme in a first transmission and to receive data packets according to a second transmission multiplexing scheme in a second transmission, wherein the first transmission is separated in time from the second transmission. The processor is configured to decode the received data packet according to a first transmission multiplexing scheme and decode the received data packet according to a second transmission multiplexing scheme, where a block error rate associated with the first transmission multiplexing scheme is higher than a block error rate associated with the second transmission multiplexing scheme.

Thus, an improved receiver is provided, allowing to receive data packets from a transmitter, such as a base station, in an efficient and reliable manner.

According to a fourth aspect, the present invention relates to a method of receiving data packets from a transmitter, in particular receiving data packets according to a hybrid automatic repeat request (HARQ) scheme or a blind repetition scheme. The method comprises the following steps: receiving a data packet in a first transmission according to a first transmission multiplexing scheme; decoding the received data packet according to a first transmission multiplexing scheme; receiving a data packet in a second transmission according to a second transmit multiplexing scheme, wherein the first transmission is separated in time from the second transmission; and decoding the received data packet according to a second transmission multiplexing scheme, wherein the block error rate associated with the first transmission multiplexing scheme is higher than the block error rate associated with the second transmission multiplexing scheme.

The above method may be implemented using a receiver according to the third aspect, such as a user entity or a terminal.

Thus, an improved method is provided, allowing to receive data packets from a transmitter, such as a base station, in an efficient and reliable manner.

According to a fifth aspect, the invention relates to a computer program product comprising program code for performing the method according to the second or fourth aspect when the program code runs on a computer.

The present invention may be implemented in hardware and/or software.

Drawings

Other embodiments of the invention will be described with reference to the following drawings, in which:

fig. 1 shows a table summarizing the latency and reliability requirements under different urlllc scenarios defined in the 3GPP TR22.862 specification;

FIG. 2 shows a schematic diagram of hybrid services support for vertical industries in a 5G network;

fig. 3 shows a schematic diagram of a 5G NR frame structure;

fig. 4 shows a schematic diagram of spatial multiplexing of uRLLC data and eMBB data;

fig. 5 is a diagram illustrating contents of control information according to an adaptive HARQ scheme;

fig. 6 shows a schematic diagram of a cellular communication network according to an embodiment;

FIG. 7 illustrates a diagram of adaptive transmission based on flexible reliability requirements, according to an embodiment;

FIG. 8 illustrates a diagram of adaptive transmission based on flexible reliability requirements, according to an embodiment;

FIG. 9 illustrates a schematic diagram of an adaptive transmission method based on flexible reliability requirements, according to an embodiment;

fig. 10 shows a schematic diagram of adaptive transmission of coexistence of urlllc and eMBB according to an embodiment;

fig. 11 shows a schematic diagram of an exemplary frame structure for multiplexing uRLLC and eMBB transmissions according to an embodiment;

fig. 12 shows a schematic diagram of adaptive transmission of coexistence of urlllc and eMBB according to an embodiment;

fig. 13 is a diagram illustrating contents of control information according to a flexible adaptive HARQ scheme;

figure 14 shows a schematic diagram of an exemplary signaling procedure according to an embodiment;

FIG. 15 illustrates a diagram of an exemplary frame structure for pre-indication, in accordance with an embodiment;

fig. 16 shows a schematic diagram of a transmission method according to an embodiment; and

fig. 17 shows a schematic diagram of a receiving method according to an embodiment.

The same reference numerals are used in different figures for identical or at least functionally equivalent features.

Detailed Description

The following description makes reference to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific aspects of the invention that may be practiced. It is to be understood that other aspects may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description is not to be taken in a limiting sense, since the scope of the present invention is defined by the appended claims.

For example, it should be understood that the disclosure relating to the described method may also apply to a corresponding apparatus or system for performing the method, and vice versa. For example, if a particular method step is described, the corresponding apparatus may comprise means for performing the described method step, even if such means are not explicitly described or shown in the figures.

Furthermore, in the following detailed description and in the claims, embodiments are described with different functional blocks or processing units, which are connected to each other or exchange signals with each other. It is to be understood that the invention also covers embodiments comprising additional functional blocks or processing units arranged between the functional blocks or processing units of the embodiments described below.

Finally, it should be understood that features of the various exemplary aspects described herein may be combined with each other, unless explicitly stated otherwise.

In order to improve data transmission in case of coexistence of urlllc and eMBB, a transmitter such as a base station in the embodiments of the present invention may use an enhanced flexible transmission scheme for multiplexing of urlllc and eMBB data within a UE, and may change the transmission multiplexing of urlllc in the coexistence area based on individual reliability targets for urlllc transmission and/or dynamic channel conditions between the transmitter and the receiver (e.g., user entity or terminal) at each transmission attempt. In the following embodiments, further details regarding the enhanced transmission scheme will be discussed with reference to fig. 7 to 9.

Fig. 6 shows a schematic diagram of a cellular communication network 600, the cellular communication network 600 comprising a transmitter 601 according to an embodiment and a receiver 631 according to an embodiment, wherein the transmitter 601 is configured to transmit data packets in the cellular communication network 600, in particular according to a hybrid automatic repeat request (HARQ) scheme or a blind repeat scheme, and the receiver 631 is configured to receive the data packets.

In an exemplary embodiment, the transmitter 601 may be implemented in a base station, particularly a next generation node B in a 5G network, and the receiver 631 may be, for example, a user entity, a mobile phone, a terminal, or a vehicle.

Further, the data packet may include a first portion and a second portion, wherein the first portion of the data packet requires higher reliability and/or lower latency than the second portion of the data packet. For example, the first packet portion is related to the urrllc data transmission service, while the second packet portion is related to the eMBB data transmission service. The data transmission service may include, for example, transport blocks.

As can be seen in fig. 6, the transmitter 601 comprises a communication interface 603 and a processor 605, the communication interface 603 being configured to transmit data packets, and the processor 605 being configured to determine a transmission multiplexing scheme for transmitting the data packets.

Similar to the transmitter 601, the receiver 631 also includes a communication interface 633 for receiving data packets and a processor 635, the processor 635 for decoding the received data packets. Further embodiments of the transmitter 601 and receiver 631 will be described below with reference to fig. 7, in which several adaptive transmissions based on different reliability targets are shown.

According to an embodiment, the processor 605 is configured to determine a first transmission multiplexing scheme for transmitting the data packet in the first transmission 701, and the communication interface 603 is configured to receive a retransmission request after transmitting the data packet in the first transmission 701.

Upon receiving the retransmission request, the processor 605 is configured to determine a second multiplexing scheme for transmitting the data packet in the second transmission 702, wherein the first transmission multiplexing scheme is associated with a higher block error rate (i.e. lower reliability requirement) than the second transmission multiplexing scheme.

Optionally, the processor 605 may also be configured to determine the second multiplexing scheme after expiration of a predetermined time interval after determining the first transmission multiplexing scheme, and/or the communication interface 603 is configured to retransmit the data packet in a second transmission having a higher reliability target after expiration of the predetermined time interval after the first transmission 701. The predetermined time interval may be a parameter from the autonomous HARQ transmission scheme.

Processor 605 is configured to determine a respective transmit multiplexing scheme that satisfies a block error rate requirement associated with a data transmission service. In another embodiment, the processor 605 may also determine a corresponding transmission multiplexing scheme for retransmitting the data packets based on the channel condition between the transmitter 601 and the receiver 631.

After the transmitter 601 transmits the data packets, the communication interface 633 of the receiver 631 is configured to receive the data packets, and the processor 635 of the receiver 631 is configured to decode the received data packets according to a corresponding transmit multiplexing scheme.

In an embodiment, the first transmission multiplexing scheme is associated with transmissions according to the first transmission scheme and the second transmission multiplexing scheme is associated with transmissions according to the second transmission scheme. In particular, the first transmission scheme may provide higher spectral efficiency than the second transmission scheme.

As can be seen from fig. 7, the block error rate when performing the first transmission 701 is higher than the second transmission 702 (i.e. has lower reliability requirements), and therefore the transmitter 601 may determine a transmission scheme for the first transmission 701 that provides a high spectral efficiency. For example, the transmitter 601 according to embodiments may first make an initial transmission 701 (e.g., NOMA, spatial multiplexing) with an overlap of urrllc and eMBB to save resources, and then use a robust transmission method, such as an Orthogonal Frequency Division Multiplexing (OFDM) scheme, to ensure higher reliability during retransmission.

By way of illustration and not limitation, the first sending scheme may include at least one of the following schemes: the first packet part is overlapped with a second packet part, in particular a superposition based transmission method such as non-orthogonal multiple access (NOMA), and/or spatial multiplexing, the second transmission scheme being different from the first transmission scheme and may comprise, for example, orthogonal scheduling (OFDM) for services and/or eMBB resource preemption for urrllc.

In general, the base station scheduler selects the correct transmission parameters, including all or part of the covariance matrix, eigenvalues, rank indicators, channel quality information, etc., based on channel state information feedback. Spatial multiplexing, which relies on multiple antennas or Multiple Input Multiple Output (MIMO) techniques, is widely used when rich multipath effects are generated due to reflections. On the other hand, non-orthogonal transmission schemes provide poor performance due to multipath and require a high operating signal-to-noise ratio (SNR).

In contrast, embodiments of the present invention may use an enhanced adaptive transmission scheme that takes into account the coexistence of urrllc and eMBB with flexible reliability targets, and may select the best multiplexing technique for each transmission attempt based on the reliability targets. Thus, embodiments of the present invention may avoid over-provisioning of resources by using relaxed transmit multiplexing at the initial transmission, which may coexist with the uRLLC service and the eMBB service in equally stringent as well as more stringent transmit multiplexing, which provides the reliability required for uRLLC retransmissions to decode within the HARQ delay range.

Since the combined reliability of the eMBB data and the urrllc data is relaxed in the initial transmission, a NOMA scheme satisfying a low reliability requirement may be used. Since orthogonal scheduling may meet high reliability requirements, orthogonal scheduling providing separate resources for uRLLC data and eMBB data may be considered for retransmission.

The enhanced adaptive transmission scheme can also be used for no HARQ, which is a dynamic transmission multiplexing method based on blind repetition, where flexible reliability targets can be introduced.

Embodiments of the invention have in particular the following advantages: firstly, an optimal sending method is selected based on a reliability target, and the requirements of uRLLC data transmission are met.

Second, Log Likelihood Ratio (LLR) quality of the soft buffer can be improved and IR gain can be maintained, compared to MCS that varies within the HARQ delay range. In case of urrllc, since the scheduling interval is short, the channel instantaneously changes slowly, and the adjustment Modulation and Coding Scheme (MCS) does not coincide with the radio condition.

Furthermore, the overlapped eMBB symbol performance may be slightly degraded; a conservative MCS scheme may be employed for urrllc; the MCS used for the urrllc does not have to be adjusted for Incremental Redundancy (IR) gains in retransmissions. Last but not least, resource efficiency for the urrllc can be obtained by adapting the transmission method.

In case of no HARQ transmission (i.e. repetition based transmission), the transmission parameters of the multiplexing scheme (e.g. spatial multiplexing or NOMA) of the same transport block in subsequent repetitions may be dynamically adjusted. Similarly, in case of HARQ based transmission with ACK/NACK messages as feedback, the transmission parameters of the adaptive HARQ scheme for the same transport block may be dynamically adjusted to provide sufficient spectral efficiency and required reliability.

Fig. 8 shows a schematic diagram of adaptive transmission based on a flexible reliability target according to an embodiment, wherein the processor 605 of the transmitter 601 may determine a corresponding transmission multiplexing scheme that can meet the reliability requirement of each data transmission.

According to the adaptive HARQ transmission scheme, the transmitter 601 may dynamically select a transmission method as shown in fig. 8, taking into account channel conditions and reliability requirements. As an example, in method 1, different superposition techniques (e.g., NOMA) and orthogonal scheduling techniques may be used for initial transmission and retransmission, respectively, within the HARQ delay of urlllc data. In method 2, different spatial multiplexing and puncturing techniques may be used within the HARQ delay range of the urrllc data. Finally, a combination of

methods

1 and 2 can be applied in method 3.

Fig. 9 shows a schematic diagram of an adaptive transmission method according to an embodiment, which is capable of meeting different reliability requirements in case of coexistence of uRLLC and eMBB. As shown in fig. 9, orthogonal scheduling may provide the highest reliability (i.e., the lowest block error rate), while the superposition-based transmission method provides the lowest reliability, but the highest spectral efficiency.

Assuming that the uRLLC service supports micro-slot (e.g., 2-OFDM symbol) based transmission and the eMBB service uses 1ms subframes, the enhanced adaptive HARQ scheme may be used to handle overlapping symbols of eMBB and uRLLC transmissions. For urrllc and eMBB data transmission, the scheme can perform both non-slot based transmission and slot based unified scheduling.

As shown in fig. 10, in the case of non-slot based transmission, the micro-slot (e.g., 2-OFDM symbol) based urrllc transmission method may be adjusted within the scheduling period of the eMBB transmission. In this case, the adaptive HARQ scheme is applied to the uRLLC symbol and the overlapping symbol of the eMBB region. In the case of a unified scheduling scheme based on time slots, adaptive HARQ transmission requires DCI (downlink control information) content of a combination of urrllc data and eMBB data.

Fig. 10 shows a schematic diagram of adaptive transmission in case of non-uniform scheduling of eMBB data and urrllc data, where the urrllc service uses transmission based on 0.125ms slots, while eMBB transmission is scheduled with 1ms subframe type, according to an embodiment.

According to an embodiment, the transmitter 601 may carefully handle overlapping symbols in the coexistence region, wherein an initial transmission of uRLLC data with relaxed reliability requirements may be performed according to a superposition based transmission scheme and subsequent transmissions with high reliability requirements may be handled using robust transmission methods (e.g. orthogonal scheduling). Therefore, the present embodiment may improve scheduling flexibility and spectral efficiency, as well as meet reliability requirements for urrllc data, and slightly reduce the performance of eMBB transmission.

Fig. 11 shows a schematic diagram of an exemplary frame structure multiplexing uRLLC and eMBB transmissions, where the uRLLC service uses transmission based on 0.1ms slots and the eMBB transmission is scheduled with 1ms subframe type, according to an embodiment.

In a further embodiment, fig. 12 shows a schematic diagram of adaptive transmission in case of non-uniform scheduling of eMBB data and urrllc data, where the urrllc service uses micro-slot based transmission (e.g. 2 or 4 or 7 OFDM symbols), whereas eMBB transmission is scheduled with 1ms subframe type.

As already explained before in fig. 10, based on the different reliability requirements of the uRLLC transmission, the transmitter can carefully handle the overlapping symbols in the coexistence area shown in fig. 12 according to different transmission schemes.

In an embodiment, the communication interface of the transmitter is further adapted to signal the respective transmission multiplexing scheme to the receiver, in particular in control information, wherein the respective transmission multiplexing scheme comprises information indicating the respective transmission scheme. Thus, the processor 635 of the receiver 631 is allowed to decode the eMBB transmission and the urrllc transmission accordingly.

As shown in fig. 13, information on a change of a corresponding transmission scheme per retransmission may be provided to the receiver 631 in control information, wherein an information element indicating a transmission method in L1 urrllc DCI signaling may be used in common with a corresponding redundancy version (RV 0). An information field needs to be added in HARQ L1 DCI signaling to explicitly indicate the desired demultiplexing scheme of uRLLC data and eMBB data that can be applied at the receiving side.

In an embodiment, the communication interface 603 of the transmitter 601 is further configured to transmit data packets to the receiver 631 using a predetermined transmit multiplexing scheme. Thereafter, the communication interface 603 transmits a Radio Resource Control (RRC) reconfiguration request to the receiver 631, wherein the RRC reconfiguration request indicates a change from transmitting packets using a predetermined transmission multiplexing scheme to transmitting packets using a corresponding transmission multiplexing scheme. Fig. 14 shows an exemplary process according to the present embodiment, wherein the process comprises the steps of:

first, the communication interface 603 of the transmitter 601 (i.e., the gNB) is configured to transmit a Radio Resource Control (RRC) reconfiguration request to the receiver 631, wherein the RRC reconfiguration request indicates a change from transmitting packets using a predetermined transmission multiplexing scheme to transmitting packets using a corresponding transmission multiplexing scheme (step 1401).

Secondly, the communication interface 603 of the transmitter 601 may signal the respective transmit multiplexing scheme to the receiver 631, in particular in control information, wherein the respective transmit multiplexing scheme comprises information indicating the respective transmit scheme (step 1403).

Thus, the receiving side 631 (i.e. the user entity) which knows the Redundancy Version (RV) may know the transmission scheme employed by the transmitter 601 to transmit the data and may select the demultiplexing method accordingly.

In case of a flexible adaptive HARQ scheme with pre-indication, an information field needs to be added in the pre-indication message to provide the desired transmission method, which is applicable for the urrllc data that needs to be applied at the receiver side. In the 5G NR protocol, the pre-indication may be part of the CORESET design with group common PDCCH, as shown in fig. 15, where the periodicity is semi-statically configured by Radio Resource Control (RRC). For more details, please see "overview of the remaining problems with preemption indication," Huawei Tdoc.

In the case of uplink, when grant-based or grant-free eMBB transmission is ongoing, the grant-free urrllc transmission may be configured by using the NOMA scheme to superimpose time or frequency resources on the ongoing eMBB transmission, and then the grant-based urrllc is used for retransmission by a different multiplexing transmission method.

Fig. 16 shows a schematic diagram of a method 1600 of transmitting a data packet to a receiver 631 according to an embodiment, in particular transmitting a data packet according to a hybrid automatic repeat request (HARQ) scheme or a blind repeat scheme.

The sending method 1600 comprises the following steps: determining 1601 a first transmission multiplexing scheme for transmitting data packets in the first transmission 701; transmitting 1603 data packets in a first transmission 701 using a first transmission multiplexing scheme; determining 1605 a second transmission multiplexing scheme for transmitting the data packets in the second transmission 702, wherein a block error rate associated with the first transmission multiplexing scheme is higher than a block error rate associated with the second transmission multiplexing scheme; the data packets are transmitted 1607 in a second transmission 702 using a second transmission multiplexing scheme, wherein the first transmission 701 is separated in time from the second transmission 702.

Fig. 17 shows a schematic diagram of a method 1700 of receiving data packets from a transmitter 601 according to an embodiment, in particular according to a hybrid automatic repeat request (HARQ) scheme or a blind repetition scheme.

The receiving method 1700 comprises the following steps: receiving 1701 a received data packet in a first transmission 701 according to a first transmission multiplexing scheme; decoding 1703 the received data packet according to a first transmission multiplexing scheme; receiving 1705 the data packet in a second transmission 702 according to a second transmit multiplexing scheme, wherein the first transmission 701 is separated in time from the second transmission 702; and decoding 1707 the received data packet according to a second transmission multiplexing scheme, wherein the first transmission multiplexing scheme is associated with a higher block error rate than the second transmission multiplexing scheme.

Although a particular feature or aspect of the disclosure may have been disclosed with respect to only one of several implementations or embodiments, such feature or aspect may be combined with one or more other features or aspects of the other implementations or embodiments as such combination may be desired and advantageous for any given or particular application. Furthermore, the terms "comprising," having, "or other variants thereof, are used in either the detailed description or the claims, and such terms are intended to be inclusive in a manner similar to the term" comprising. Also, the terms "exemplary," "by way of example," and "such as" are merely examples, which are not optimal or optimal. The terms "coupled," "connected," and their derivatives may be used. It will be understood that these terms may be used to indicate that two elements co-operate or interact with each other, whether in direct physical or electrical contact, or whether they are not in direct contact with each other.

Although specific aspects have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific aspects shown and described without departing from the scope of the present invention. This application is intended to cover adaptations or variations of the specific aspects discussed herein.

Although the elements of the following claims are recited in a particular sequence with corresponding labeling, unless a claim otherwise recites a sequence to achieve some or all of these elements, it is not necessarily intended that these elements be limited to being performed in this particular sequence.

Many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing. Of course, those skilled in the art will readily recognize that there are many applications of the present invention other than those described herein. While the invention has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the scope of the invention. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described herein.

Claims

1. A transmitter (601) for transmitting data packets to a receiver (631), in particular according to a hybrid automatic repeat request (HARQ) scheme or a blind repetition scheme, the transmitter comprising:

a communication interface (603) for transmitting the data packet; and

a processor (605) for

-determining a first transmission multiplexing scheme for transmitting the data packets in a first transmission (701), and

-determining a second transmission multiplexing scheme for transmitting the data packets in a second transmission (702),

wherein the estimated block error rate associated with the first transmission multiplexing scheme is higher than the estimated block error rate associated with the second transmission multiplexing scheme, and the first transmission (701) is separated in time from the second transmission (702).

2. The transmitter (601) of claim 1,

the communication interface (603) is configured to receive a retransmission request after sending the data packet in the first transmission (701), the retransmission request requesting retransmission of the data packet; and wherein the one or more of the one,

the processor (605) is configured to determine the second multiplexing scheme upon receiving the retransmission request.

3. The transmitter (601) of any of the preceding claims, wherein the processor (605) is configured to determine the second multiplexing scheme after expiration of a predetermined time interval after determining the first transmission multiplexing scheme, and/or wherein the communication interface (603) is configured to retransmit the data packet in the second transmission (702) after expiration of the predetermined time interval after the first transmission (701).

4. The transmitter (601) according to any of the preceding claims, wherein the data packet comprises a first data packet part and a second data packet part, wherein the first data packet part of the data packet requires a higher reliability and/or a lower latency than the second data packet part.

5. The transmitter (601) of claim 4, wherein the first data packet part is associated with a data transmission service, in particular with a uRLLC service, and wherein the processor (605) is configured to determine the respective transmission multiplexing scheme that fulfils a block error rate requirement associated with the data transmission service.

6. The transmitter (601) of claim 4 or 5, wherein the second data packet portion is associated with a second data transmission service, in particular with an eMBB.

7. The transmitter (601) of any of the preceding claims, wherein the first transmission multiplexing scheme is associated with transmissions according to a first transmission scheme and the second transmission multiplexing scheme is associated with transmissions according to a second transmission scheme.

8. The transmitter (601) of claim 7, wherein the first and second transmission schemes comprise at least one of: superimposing the first packet portion with the second packet portion, in particular a superposition-based transmission method such as non-orthogonal multiple access (NOMA), and/or spatial multiplexing, coding scheme, modulation, preemption, puncturing, or scheduling, and wherein the second transmission scheme is different from the first transmission scheme.

9. The transmitter (601) of claim 7 or 8, wherein the first transmission scheme provides a higher spectral efficiency than the second transmission scheme.

10. The transmitter (601) of any of the preceding claims, the processor (605) further configured to determine the respective transmission multiplexing scheme for retransmitting the data packets based on channel conditions between the transmitter (601) and the receiver (631).

11. The transmitter (601) of any one of the preceding claims, the communication interface (603) further being configured to (631) signal the receiver the respective transmission multiplexing scheme, in particular in control information, wherein the respective transmission multiplexing scheme comprises information indicating the respective transmission scheme.

12. The transmitter (601) of any of the preceding claims, the communication interface (603) further being configured to transmit the data packets to the receiver (631) using a predetermined transmit multiplexing scheme.

13. The transmitter (601) of claim 12, the communication interface (603) further configured to:

transmitting a reconfiguration message to the receiver (631), wherein the reconfiguration message indicates one or more predetermined sets of transmission multiplexing schemes, the transmission multiplexing schemes being associated with redundancy versions and/or transmission numbers; and

signaling the receiver the one or more predetermined sets in the reconfiguration message, wherein the dynamic activation of one of the one or more predetermined sets is performed by the control information.

14. The transmitter (601) of claim 12 or 13, the communication interface (603) further being configured to:

transmitting a reconfiguration message to the receiver (631), wherein the reconfiguration message indicates a change in transmission of the data packets from using the predetermined transmission multiplexing scheme to using the respective transmission multiplexing scheme; and

signaling the receiver (631) the respective transmission multiplexing scheme, in particular in control information, wherein the respective transmission multiplexing scheme comprises information indicating the respective transmission scheme.

15. A method (1600) of transmitting data packets to a receiver (631), in particular according to a hybrid automatic repeat request (HARQ) scheme or a blind repetition scheme, the method (1600) comprising:

determining (1601) a first transmission multiplexing scheme for transmitting the data packet in a first transmission (701);

-transmitting (1603) the data packets in the first transmission (701) using the first transmission multiplexing scheme;

determining (1605) a second transmission multiplexing scheme for transmitting the data packets in a second transmission (702), wherein the first transmission multiplexing scheme is associated with a higher block error rate than the second transmission multiplexing scheme; and

transmitting (1607) the data packet in the second transmission (702) using the second transmission multiplexing scheme, wherein the first transmission (701) and the second transmission (702) are separated in time.

16. A receiver (631) for receiving data packets from a transmitter (601), in particular according to a hybrid automatic repeat request (HARQ) scheme or a blind repetition scheme, the receiver (631) comprising:

a communication interface (633) for receiving the data packets in a first transmission (701) according to a first transmission multiplexing scheme and in a second transmission (702) according to a second transmission multiplexing scheme, wherein the first transmission (701) is separated in time from the second transmission (702); and

a processor (635) configured to decode the received data packets according to the first transmission multiplexing scheme and decode the received data packets according to the second transmission multiplexing scheme, wherein a block error rate associated with the first transmission multiplexing scheme is higher than a block error rate associated with the second transmission multiplexing scheme.

17. A method (1700) of receiving data packets from a transmitter (601), in particular according to a hybrid automatic repeat request (HARQ) scheme or a blind repetition scheme, the method (1700) comprising:

receiving (1701) the data packet in a first transmission (701) according to a first sending multiplexing scheme;

decoding (1703) the received data packet according to the first transmission multiplexing scheme;

receiving (1705) the data packet in a second transmission (702) according to a second transmit multiplexing scheme, wherein the first transmission (701) is separated in time from the second transmission (702); and

decoding (1707) the received data packet according to the second transmission multiplexing scheme, wherein a block error rate associated with the first transmission multiplexing scheme is higher than a block error rate associated with the second transmission multiplexing scheme.

18. A computer program comprising a program code for performing the method (1600) of claim 15 or the method (1700) of claim 17 when the program code runs on a computer.