CN111886844B

CN111886844B - Method and user equipment for transmitting data

Info

Publication number: CN111886844B
Application number: CN201980010798.9A
Authority: CN
Inventors: 欧麦尔·萨利姆; 赛巴斯钦·华格纳; 布鲁诺·杰裘克斯
Original assignee: JRD Communication Shenzhen Ltd
Current assignee: JRD Communication Shenzhen Ltd
Priority date: 2018-02-09
Filing date: 2019-01-25
Publication date: 2023-04-04
Anticipated expiration: 2039-01-25
Also published as: GB2571073A; CN111886844A; WO2019154105A1; GB2571073B; GB201802187D0

Abstract

A method and user equipment for transmitting data are disclosed, wherein control and scheduling information is sent after the data associated therewith. A device stores a signal that is received, possibly containing data for the device, until the end of a time at which scheduling information may be received. If scheduling information related to the signal is received, the scheduling information is decoded to retrieve the data.

Description

Method and user equipment for transmitting data

Technical Field

The following disclosure relates to transmission of downlink data, and more particularly to a system for improving downlink communication efficiency.

Background

Wireless communication systems, such as third generation (3G) mobile telephone standards and technologies are well known. Such 3G standards and techniques are developed by the third generation partnership project (3 GPP). Third generation wireless communications have typically been developed to support macro-handset communications. Communication systems and networks have evolved towards broadband and mobile systems.

In a cellular Radio communication system, a User Equipment (UE) is connected to a Radio Access Network (RAN) via a Radio link. The RAN comprises a set of base stations that provide radio links to UEs located in cells covered by the base stations, and is connected to a Core Network (CN) that provides overall Network control. As will be appreciated, the RAN and CN each perform respective functions for the entire network. For convenience, the term cellular network will be used to refer to the combined RAN and CN, and it will be understood that this term is used to refer to the various systems for performing the disclosed functions.

The third generation partnership project has developed a so-called Long Term Evolution (LTE) system, evolved UMTS terrestrial radio access network (E-UTRAN), as a mobile access network, in which one or more macro cells are covered by base stations called enodebs or enbs (evolved nodebs). Recently, LTE is evolving further towards so-called 5G or NR (new radio) systems, where one or more cells are covered by base stations called gnbs. NR is proposed to use an Orthogonal Frequency Division Multiplexing (OFDM) physical transmission scheme.

One trend in wireless communications is to provide channels with low delay and high reliability. For example, NR is intended to support Ultra-Reliable and Low-Latency Communications (URLLC). A user plane delay of 1 millisecond is proposed with a reliability of 999999%.

Communication on the Physical radio link is defined by a plurality of channels, such as a Physical Downlink Control Channel (PDCCH) for transmitting Control Information, in particular Downlink Control Information (DCI), which defines how data is transmitted to the UE over a Physical Downlink Shared Channel (PDSCH). Successful reception of data at the UE requires reception and decoding of the PDCCH channel and PDSCH channel.

The DCI in the PDCCH carries scheduling and control information (PDSCH) related to data. The scheduling information primarily indicates to the UE which time-frequency resources are allocated for its related data (PDSCH) transmission. The control information for downlink transmission in the DCI includes other necessary parameters that enable the UE to decode the scheduling data. These parameters may include, for example, modulation, coding scheme, parameters related to hybrid automatic repeat request and parameters related to uplink response.

The following terminology is generally used for downlink physical channels, in particular PDCCH. Specific examples relate to NR, but these principles apply to other physical channel protocols.

A Resource Block (RB) is the smallest unit of time/frequency resources that can be allocated to a user. The resource block has a frequency of x-kHz width and a time of 1 slot length. The number of subcarriers used per resource block of the PDCCH is 12, the exact value x depends on the subcarrier spacing (x =12 × scs), which may be 15khz, 30khz, 60khz, etc. The default slot duration in NR is 14 OFDM symbols in terms of time, but there may also be a minimum slot duration (e.g., 1,2, 3, up to 13 OFDM symbols). The exact duration (milliseconds) of the slot depends on the constituent number of OFDM symbols and SCS, e.g., 1 slot is 1ms long for 15KHZ SCS and 14 OFDM symbols.

A 1 Resource Element Group (REG) is equal to 1 RB on 1 OFDM (Orthogonal Frequency Division Multiplex) symbol.

The 1 Control-Channel Element (CCE) consists of 6 REGs.

The PDCCH consists of one or more CCEs (e.g., L ∈ {1,2,4,8 }). This number is defined as the CCE Aggregation Level (AL).

For PDCCH blind decoding, the AL set monitored by the UE and the number of PDCCH candidates per aggregation level per CCE of DCI format size may be configured.

For each serving cell, each UE is configured with multiple control resource sets (CORESETs) to monitor the PDCCH. Each control resource set is defined by: starting OFDM symbol, duration (consecutive symbols, up to 3), RB set, CCE-to-REG mapping (and REG bundle size at interleaving mapping).

B consecutive REGs in time (and frequency if B is larger than the size of the control resource set in the symbol) form one REG bundle.

The distributed resource mapping is realized by interleaving, and the interleaving is operated on the REG bundle. B =6 if it is a non-interleaved CCE-to-REG mapping.

In the case of interleaved CCE-to-REG mapping, B e {2,6} represents a 1 or 2 symbol set of control resources, and B e {3,6} represents a 3 symbol set of control resources.

The search space of 1 PDCCH at the aggregation level L of a CCE is defined by a set of PDCCH candidate sets at that aggregation level of the CCE.

Cellular wireless communication systems typically use HARQ (Hybrid Automatic Repeat reQuest) based protocols to improve reliability, but at the cost of increased delay. It is a challenge to meet the delay requirements of URLLC service using the HARQ protocols of PDCCH and PDSCH, and new methods may be needed to transmit these channels.

The term "reliability" in TR 38.802 is commonly defined by 3GPP as the probability of success R of transmitting X bits within L seconds. L is the time required to transfer a small data packet from a radio protocol layer 2/3SDU entry point to a radio protocol layer 2/3SDU exit point of the radio interface at a certain channel quality Q (e.g. coverage edge).

The delay bound L includes transmission delays, processing delays, retransmission delays (if any), and queuing/scheduling delays (including scheduling requests and grant receptions, if any).

This document also states that spectral efficiency should be considered when trying to achieve a reliability index.

Regarding the reliability index of URLLC scenario, NR considers in TR 38.913 that "the reliability requirement of a normal URLLC one-time transmission is: the reliability of transmitting 32-byte data packets is (1-10) within 1 millisecond of user plane delay ^-5 )。”

The reliability R can be given by the following equation, considering a normal one-time transmission (i.e. no HARQ retransmission or repetition). R = R _c R _d

Wherein R is _c And R _d Indicating the probability of successful PDCCH and PDSCH transmission, respectively. For simplicity, it is assumed thatThe impact of the alarm probability is negligible (i.e., an error due to the UE erroneously effectively detecting the PDCCH without DCI transmission). A sufficiently large CRC (Cyclic Redundancy Check), e.g. 24 bits, may achieve this when encoding the DCI.

In contrast, the probability of erroneous packet transmission P (= 1-R) is given by the following equation:

P＝1-(1-P _c )(1-P _d )

wherein P is _c And P _d Indicating the probability of erroneous PDCCH and PDSCH transmissions, respectively.

Thus, for example, the error probability (e.g., P) of a channel may be combined _c ＝8·10 ^-6 And P _d ＝2·10 ^-6 Etc.) to achieve an NR reliability index (> 99.999% reliability or conversely,<error probability of 0.001%).

In the case of multipoint transmission, a number of additional factors control the reliability of the transmission. For example, assuming no HARQ combining, for a conventional two-transmission (as shown in fig. 1), the reliability can be given by the following equation: r = R _c R _d1 +(1–R _c )R _DTX R _c R _d2 +R _c (1–R _d1 )R _N R _c R _d2

Wherein R is _d1 And R _d2 Respectively representing the probability of successful PDSCH initial transmission and the probability of successful PDSCH retransmission; r _DTX Represents the probability that the gNB detects DTX or NACK (Negative acknowledgement character) when the UE "transmits" DTX (Discontinuous Transmission) in the UL (i.e., does not transmit anything); r _N Indicating the probability that the gNB detects DTX or NACK when the UE sends NACK.

On the right side of the above equation, the first term of the summation indicates successful reception of the initial transmission, the second term indicates successful reception of the retransmission when PDCCH detection fails, and the third term indicates successful reception of the retransmission when initial PDSCH decoding fails.

There are many ways to improve the reliability of control-channel transmission, but these may involve the use of larger transmission resources. There may not be enough control channel resources to schedule transmissions to fully utilize the data transmission capacity, and thus such data transmission capacity may be left unused, resulting in inefficient use of resources.

Multiple transmissions with or without adaptive HARQ may improve reliability but may be limited under delay constraints (Latency Constraint). In heavy traffic (traffic) situations combined with strict delay requirements, the network most likely has to best-effort with a single transmission, while satisfying delay and reliability.

For PDCCH design, the aggregation level is typically increased when the network realizes that the user cannot decode the control information correctly. Increasing the aggregation level means that more resources are used to encode the control information, which results in a reduction of the coding rate and thus a higher robustness of the transmission against errors (robustness). Using a higher aggregation level consumes a lot of resources, which results in the inability of other users to use the control resources.

Fig. 1 shows a schematic diagram of a transmission resource. Each slot 100 is divided into a control region 101 and a data region 102. The control region is used to transmit control information, such as PDCCH, to schedule transmission of the PDSCH channel 103 in the data region of the time slot. In the example of fig. 1, in the first slot, the PDCCH (shown in dashed lines) for a particular UE occupies all the control resources, but the associated PDSCH (also shown in dashed lines) for that UE utilizes only a subset of the data resources. The PDCCH may require a large amount of resources due to the use of a higher aggregation level to improve reliability, e.g., due to the UE being located at a cell edge or a poor channel condition.

The data resources 104 are therefore unused, but cannot be utilized by another UE due to lack of control resources on which scheduled transmissions can take place. Since there is no control resource available to transmit the required PDCCH, at this occasion, another UE is not served and needs to be served and its data is available on the gNB at the same time interval, which may break the delay constraint of other UE services. This occurs due to PDCCH blocking even if there are resources available to transmit data.

The present invention seeks to address at least some of the unresolved problems in the art.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed claims, nor is it intended to be used as an aid in determining the scope of the claimed claims.

There is provided a method of transmitting data from a base station to a user equipment in a wireless cellular communication network, the method comprising the steps of: transmitting a signal representing data from a base station to a UE over a radio link; receiving and storing signals representing data at the UE; transmitting scheduling information from the base station to the UE after starting transmission of a signal representing data, wherein the scheduling information is used to identify a resource for transmitting the signal representing data; receiving the scheduling information at the UE; at the UE, the scheduling information is utilized to recover data from the stored signal.

The scheduling information may be transmitted after completion of transmission of the signal representing the data.

The scheduling information may indicate an end of a data transmission signal, the data transmission signal being during transmission or after the end of the control transmission signal.

The signal representing the data may be transmitted in a data transmission region of a first time slot and the scheduling information may be transmitted in a control region of a second time slot.

Signals representing data may be transmitted on the PDSCH and scheduling information on the PDCCH.

The scheduling information may be transmitted in a downlink control information message.

The signal representing the data may be transmitted in a first time slot and the scheduling information in a subsequent time slot.

The scheduling information may be transmitted in a time slot adjacent to the first time slot.

The scheduling information may not be transmitted in a time slot adjacent to the first time slot.

The scheduling information may include an indication of time domain PDSCH resources including signals representing data with a row index of a Radio Resource Control (RRC) configuration table.

Other rows may be configured in the RRC configuration table to represent data transmitted prior to the scheduling information. The method may further comprise the steps of: prior to transmitting a signal representing data, transmitting to the UE an indication of: the data signals may be received before scheduling information related to those data signals.

The indication may be an RRC message.

The indication may be sent in accordance with controlling resource availability.

The indication may be sent according to the class or type of the UE.

The indication may be sent as a broadcast message or as a message to a particular UE.

The indication may also include an indication of a maximum delay between the signal representing the data and the scheduling information.

The maximum delay may be indicated as a number of PDCCH occasions (occasions).

The indication may also include an indication of frequency resources that may be used for transmission of data prior to the relevant scheduling information.

There is also provided a method of transmitting data from a base station to a user equipment in a wireless cellular communication network, the method comprising the steps of: transmitting a signal representing data from a base station to a UE over a radio link; after transmission of a signal representing data is started, scheduling information is transmitted from the base station to the UE, wherein the scheduling information is used to identify resources used to transmit the signal representing data.

The scheduling information may indicate an end of a data transmission signal, the data transmission signal being during transmission or after the end of a control transmission signal.

The scheduling information may be transmitted after the transmission of the signal representing the data is completed.

The signal may indicate that data is transmitted in the data transmission region of the first time slot and scheduling information is transmitted in the control region of the second time slot.

A signal representing data may be transmitted on the PDSCH and scheduling information may be transmitted on the PDCCH.

The scheduling information may be transmitted in a message of downlink control information.

A signal representing data may be transmitted in a first time slot and scheduling information may be transmitted in a subsequent time slot.

The indication may include an indication of time domain PDSCH resources including signals representing data, the time domain PDSCH resources utilizing a row index of an RRC configuration table.

Other rows may be configured in the RRC configuration table to represent data transmitted prior to the scheduling information.

The method may further comprise the steps of: prior to transmitting a signal representing data, transmitting to the UE an indication of: the data signals may be received before scheduling information related to those data signals.

The indication may be an RRC message.

The indication may be sent according to the class or type of the UE.

The indication may be sent in the form of a broadcast message.

The indication may be sent to the particular UE in the form of a message.

The maximum delay may be indicated as a number of PDCCH occasions.

There is also provided a base station configured to perform the above method.

There is also provided a method of transmitting data from a base station to a user equipment in a wireless cellular communications network, the method comprising the steps of: receiving signals representing data at the UE and storing the signals; transmitting scheduling information from the base station to the UE after starting transmission of a signal representing data, wherein the scheduling information is used to identify a resource for transmitting the signal representing data; receiving scheduling information at the UE, the scheduling information identifying resources for transmitting signals representing data; at the UE, the scheduling information is utilized to recover data from the stored signal.

The scheduling information may be received after completion of reception of the signal representing the data.

A signal representing data may be received in a data region of a first time slot and scheduling information may be received in a control region of a second time slot.

Signals representing data may be received on the PDSCH and scheduling information may be received on the PDCCH.

The scheduling information may be received in a downlink control information message.

A signal representing data may be received in a first time slot and scheduling information may be received in a subsequent time slot.

The scheduling information may be received in a time slot adjacent to the first time slot.

The scheduling information may not be received in a time slot adjacent to the first time slot.

The indication may include an indication of time domain PDSCH resources including signals representing data, the time domain PDSCH resources utilizing row indices of an RRC configured table.

The method may further comprise the steps of: prior to receiving a signal representing data, receiving an indication that the data signal was received prior to scheduling information related to the data signal.

The indication may be an RRC message.

The indication may be received in the form of a broadcast message.

The indication may be received as a message to a particular UE.

The maximum delay may be indicated as a number of PDCCH occasions.

The indication may also include an indication of frequency resources on which signals representing data prior to the relevant scheduling information may be received.

The UE may store signals representing the data to at least achieve the indicated maximum delay.

A UE configured to perform the above method is also provided.

The non-transitory computer readable medium may comprise at least one of the group of: hard disks, CD-ROMs, optical storage devices, magnetic storage devices, read-only memories, programmable read-only memories, erasable programmable read-only memories, EPROMs, electrically erasable programmable read-only memories, and flash memories.

Drawings

Further details, aspects and embodiments of the invention will be described, by way of example only, with reference to the accompanying drawings. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. To facilitate understanding, similar reference numerals have been included in the corresponding figures.

Fig. 1 is a schematic diagram of a transmission resource with regular scheduling according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a transmission resource using reverse-scheduling (Back-scheduling) according to an embodiment of the present invention;

fig. 3 is a diagram of a data transmission and reception method with reverse scheduling according to an embodiment of the present invention.

Fig. 4 is a schematic diagram of the benefit of the delay of backward scheduling in case of PDCCH blocking provided by the embodiment of the present invention;

FIG. 5 is a diagram of different possibilities for reverse scheduling delay between control and data provided by an embodiment of the present invention;

fig. 6 and fig. 7 are schematic diagrams illustrating simulation results of data transmission using reverse scheduling according to an embodiment of the present invention.

Detailed Description

Those skilled in the art will recognize and appreciate that the specifics of the described examples are merely illustrative of some embodiments and that the teachings set forth herein are applicable in a variety of alternative settings.

Fig. 2 shows a schematic diagram of a transmission resource in which data is transmitted before control information according to the method shown in fig. 3.

At step 30, data is available for transmission from the base station to the UE. In step 31 it is identified that data transmission resources in the upcoming time slot are available, but no control resources are available for transmitting PDCCH indications for data scheduling. This is the situation shown in fig. 1.

In step 32, the base station transmits a signal 20 representing data using the available resources, although the PDCCH transmission is not first made. In step 33, the signal 20 is received by the UE, which has been configured to monitor transmissions, even in the absence of relevant scheduling information, and the UE saves the received signal for later processing.

In step 34 the base station identifies the available control resources in the subsequent time slot 21 and transmits scheduling information 22 using those resources, which scheduling information relates to the already transmitted data 20. Transmitting the scheduling information after the data related to it may be referred to as reverse scheduling.

In step 35, the UE receives the scheduling information 22 and can therefore identify that the previously received signal is intended for the UE. In step 36, the ue decodes the previously received signal using the scheduling information and retrieves the data. The scheduling information is typically included in a DCI message.

The scheduling information must indicate time domain resources allocated to the relevant PDSCH. In conventional systems, this is achieved by including a reference to a row (row) in the RRC configuration table, which defines the slot offset, starting symbol and length, and PDSCH mapping type. For example, the technique can be adapted to a reverse scheduling system by adding other rows to the RRC configured table. These additional rows have slot offsets and starting symbol combinations so that reverse scheduling can be performed. One option is to introduce a new row with a negative slot offset value in the table. The presence of a row relating to reverse scheduling may be used as an indicator for the UE to configure itself to receive reverse scheduling data, but this arrangement is rather static and may be undesirable.

The methods of fig. 2 and 3 thus improve resource utilization because most of the data resources are utilized and delay is reduced because the UE is ready to decode data once it receives the scheduling information. Demodulation and decoding can be very fast because the entire data set is available in memory once the scheduling information is received. Conversely, if the base station waits for available control and data resources in the same time slot, the transmission of data has not yet begun.

Sending scheduling information after the data has been sent requires the UE to speculatively monitor the signals in the data resources and save the received signals in case the scheduling information subsequently indicates that the signals are intended for the UE. Such monitoring may increase power consumption because the UE cannot enter sleep mode if it does not receive scheduling information, and may require additional memory to store received signals until they are confirmed to be UE-independent. However, resource efficiency can be improved and delay can be reduced.

Fig. 4 illustrates the benefit of the delay of the proposed invention compared to conventional transmission in case of control resource shortage. Fig. 4 (a) shows a conventional method in which control and data may be transmitted in the first available slot after a data packet for transmission is received by a base station. Tw denotes a waiting time before starting transmission, and Tt is a total transmission time of data and control. Tp is the processing time of the UE, giving the total duration between the availability of data packets for transmission by the UE and the completion of the T-decoding.

Fig. 4 (b) shows a conventional method in which insufficient control resources are available at the first transmission. Thus, the control and data are scheduled in the next available slot, providing a larger latency Tw, and therefore a larger total time T.

In contrast, in fig. 4 (c) where the control resources are short in the first case as shown in fig. 4 (b), data is still transmitted in available data resources at the first transmission, and then control information is transmitted in the next available control case, please refer to earlier transmitted data. Compared to the conventional method in fig. 4 (b), there is a significant improvement in the waiting time Tw and the total time T due to the lack of control resources. Thus, the transmission resources can be better utilized and the overall delay of the data transmission is reduced in case the control resources limit the transmission possibilities.

The time margin (time margin) obtained by using the reverse scheduling is useful for applications/users requiring low delay and high reliability. In some cases, this time margin may allow the user to meet their delay goals. In other cases, the time margin may translate into a likelihood of retransmission if the first packet fails to decode. The user may then attempt to combine the two retransmissions to achieve better decodability of the data packet. This increases the reliability of the data over a time range.

In the above example, the scheduling information has been transmitted in the first control resource after the data transmission. However, the scheduling information may be transmitted at any time after the data transmission. Longer delays increase the total transmission time and may increase the storage requirements of the UE, so it may be desirable to limit the total allowable delay. However, some delays may increase flexibility, for example, in the case where the first control resource is fully occupied after data transmission. As shown in fig. 5, the scheduling resources may be transmitted in the second time slot/transmission opportunity after the data. Longer delays are possible and may lead to further improvements, but at the same time also increase the power consumption and memory requirements of the UE. The maximum delay may be defined according to the class/category of the UE supporting reverse scheduling. For example, for certain classes of UEs, such as medical devices capable of communication, autonomous cars for communication, sensitive industrial controls, etc., the power consumption and the additional cost of storage can be appropriately weighed to improve performance and quality of service in terms of latency and reliability. For example, such a UE may allow for greater latency than a budget UE where manufacturing costs are more important than performance. The maximum delay may be defined according to UE category or specifically for the UE. The maximum allowable delay may be defined as a time value, a number of slots, a PDCCH occasion, or any other suitable indicator.

In the above example, the scheduling information is transmitted after the base station completes the data transmission. In modern wireless systems like 5G NR, the occasion for PDCCH transmission can be configured anywhere in one slot and data can be scheduled to be 1 OFDM symbol long, up to multiple slots. These functions, in combination with reverse scheduling, may result in an arrangement where the data (PDSCH) will start before the control starts (due to reverse scheduling) and its end points may be in the middle of the control (PDCCH) transmission, even after the control transmission ends.

The activation of the reverse scheduling system may be controlled by the RAN, in particular the base station, and/or the CN. This configuration may be done on a cell-by-cell basis for a group of UEs or for individual UEs. The configuration may also be varied to allow for changes in demand over time. When control resources are not scarce, the functionality may not be configurable to minimize power consumption of the UE, and may be enabled when control resources are limited.

The above techniques may be more suitable for certain classes of UEs. For example, for a UE with a permanent power source (rather than battery powered), power consumption is less important, and thus such a UE may be more easily configured to receive reverse scheduled transmissions. Accordingly, activation of the reverse scheduling system may be performed according to the rank of the UE. The reverse scheduling function may be activated according to the category of the UE. For example, UEs communicating with URLLC are more likely to benefit from the system due to the stringent delay requirements for such services.

In principle, the signaling for activating or deactivating reverse scheduling may be in the form of broadcast signaling at the cell level or in the form of a specific group or a specific user, although the broadcast signaling may have a considerable overhead when transmitted so that it can be decoded by all UEs in the cell. Due to the nature and good applicability of some specific users (e.g., URLLC users), this signaling may preferably be user-specific. When the traffic in a cell is heavy and the network assumes certain potential PDCCH blocking scenarios, which may lead to delays and thus put requirements on the reliability of the UE, the network may send RRC signaling to the active URLLC users in the cell.

The above disclosure is provided in the context of time slots divided into predefined control and data regions. However, some wireless standards (e.g., 5G NR) allow for more flexible transmission mechanisms to be employed, including scheduling slot-based data, non-slot-based data, and using minislots for different users simultaneously. Also, NR allows the network to use different numbers for different durations and different frequency intervals. The principle of allowing the transmission of data to start before the transmission of the relevant scheduling information starts is equally applicable to such other formats.

Some wireless standards may provide very large bandwidths available for data transmission, for example a 5G NR may operate at millimeter wave frequencies with very large bandwidth carriers. Due to storage requirements, it may be impractical in such systems to monitor and store the full bandwidth to take advantage of reverse scheduling. The frequency resources on which data with reverse scheduled control transmissions may be transmitted may therefore be limited to a subset of the total bandwidth available. The UE then only needs to monitor and store the relevant frequency resources, thereby reducing the storage requirements. A subset of the carrier bandwidth (or Physical Resource Block (PRB) range) may be configured to the UE as part of the reverse scheduling configuration. Then, the UE monitors and records only the configured frequency resources for reverse scheduling of data. In another example, reverse scheduling resources may be limited to only the active bandwidth portion of the UE.

The following is a list of simulation results to illustrate the potential benefits of a reverse scheduling system.

Fig. 6 shows example results showing PDCCH blocking probability for PDCCH bandwidth. These results are based on four users to be scheduled per transmission opportunity. Each UE may use an aggregation level of 4,8, or 16 with a respective probability of 0.5, 0.45, 0.05. The subcarrier spacing is assumed to be 15kHz and the results are based on 1 million independent transmission occasions. These results show that normal scheduling (transmission of control and data in the same slot), reverse scheduling allowing transmission of scheduling information only in the next slot (1 opportunity), and reverse scheduling allowing transmission of scheduling information after a maximum of 2 opportunities.

Fig. 6 shows a significant reduction in PDCCH blocking probability. For a set of points at PDCCH resources of 40MHz, conventional scheduling results in a blocking probability of 3.2%. In contrast, the PDCCH blocking probability drops to 0.79% when reverse scheduling of a single occasion is allowed. This is a very important advantage, which may be very important for low latency users. In addition to allowing the base station to reverse schedule at 2 transmission occasions, the blocking probability drops to only 0.19%.

The advantages of reverse scheduling are particularly significant when the blocking probability is relatively low (in the possible working range of URLLC services). These services have strict delay and reliability constraints and therefore require a low blocking probability. As mentioned above, the additional cost of expanding memory and higher power consumption of UE types using such services, such as medical devices, networked vehicles and industrial controls, may be suitable tradeoffs to improve performance, particularly in terms of latency and reliability.

These results also show little advantage, for example due to 20MHz and 30MHz bandwidth, and due to scarce resources, the blocking probability is very high. This is due to the fact that most transmission occasions lack PDCCH resources for scheduling active users. However, even for non-URLLC services, such a scheme is not practical and not a significant problem.

Fig. 7 shows PDCCH blocking probabilities for varying numbers of users. PDCCH resources are defined to be equivalent to a bandwidth of 50MHz in a PRB and each UE uses an aggregation level of 4,8 or 16 with probabilities of 0.5, 0.45 and 0.05, respectively. The subcarrier spacing was 15KHz and 100 ten thousand independent transmissions were calculated.

The results of fig. 7 confirm the benefits of PDCCH reverse scheduling on the conventional scheduling scheme. With a PDCCH blocking probability of 0.001 (0.1%), the conventional scheme can accommodate 3 users in each scheduling interval. In contrast, the scheme for reverse scheduling on a single occasion accommodates 4 users, with the same resources and the same blocking probability in each scheduling interval. When each scheduling interval is the same resource amount and the same blocking probability, the reverse scheduling in two occasions can support 4 users.

For 4 users scheduled for fixed PDCCH resources in each transmission occasion, the conventional scheme results in a blocking probability of 0.35% for PDCCH, while reverse scheduling at 1 and 2 occasions results in blocking probabilities of 0.019% and 0.0004%, respectively. Thus, even single-occasion reverse scheduling can provide more than 10 times the benefit in terms of blocking probability. This advantage translates directly into better system spectrum and utilization and, more importantly, more users achieving a given latency goal.

Although not shown in detail, any device or apparatus forming part of a network may comprise at least a processor, a memory unit, and a communication interface, wherein the processor unit, the memory unit, and the communication interface are configured to perform the method of any aspect of the invention. Further options and choices are described below.

The signal processing functions of embodiments of the present invention, particularly the gNB and the UE, may be implemented using computing systems or architectures known to those skilled in the art. Computing systems such as desktop, laptop or notebook computers, handheld computing devices (PDAs, cell phones, palmtop computers, etc.), mainframes, servers, clients, or any other type of special or general purpose computing device as may be desirable or appropriate for a given application or environment may be used. A computing system may include one or more processors, which may be implemented using a general or special purpose processing engine such as, for example, a microprocessor, microcontroller or other control module.

The computing system may also include a main Memory, such as a Random Access Memory (RAM) or other dynamic Memory, for storing information and instructions to be executed by the processor. Such main memory may also be used for storing temporary variables or other intermediate information during execution of instructions to be executed by the processor. The computing system may also include a Read Only Memory (ROM) or other static storage device for storing static information and instructions for the processor.

The computing system may also include an information storage system that may include, for example, a media drive and a removable storage interface. The media Drive may include a Drive or other mechanism to support fixed or removable storage media, such as a hard disk Drive, a floppy disk Drive, a magnetic tape Drive, an optical disk Drive, a Compact Disc (CD) or Digital Video Drive (DVD), a read or write Drive (R or RW), or other removable or fixed media Drive. The storage media may include, for example, a hard disk, floppy disk, magnetic tape, optical disk, CD or DVD, or other fixed or removable medium that is read by and written to by a media drive. The storage media may include a computer-readable storage medium having stored therein particular computer software or data.

In alternative embodiments, the information storage system may include other similar components for allowing computer programs or other instructions or data to be loaded into the computing system. These components may include, for example, removable storage units and interfaces, such as a program cartridge and cartridge interface, removable memory (for example, a flash memory or other removable memory module) and memory slot, and other removable storage units as well as interfaces that allow software and data to be transferred from the removable storage unit to the computing system.

The computing system may also include a communication interface. Such communication interfaces may be used to allow software and data to be transferred between the computing system and external devices. Examples of a communications interface may include a modem, a network interface (e.g., an ethernet or other NIC card), a communications port (e.g., a Universal Serial Bus (USB) port), a PCMCIA slot and card, etc. Software and data transferred via the communications interface are in the form of signals which may be electronic, electromagnetic, optical or other signals capable of being received by the communications interface medium.

In this document, the terms "computer program product," "computer-readable medium," and the like may be used generally to refer to tangible media, such as memory, storage devices, or storage units. These and other forms of computer-readable media may store one or more instructions for use by a processor comprising a computer system, to cause the processor to perform specified operations. Such instructions, generally referred to as "computer program code" (which may be grouped in the form of computer programs or other groupings), when executed, enable the computing system to perform functions of embodiments of the present invention. Note that the code may directly cause the processor to perform specified operations, be compiled to do so, and/or be combined with other software, hardware, and/or firmware elements (e.g., libraries for performing standard functions) to do so.

In embodiments where the elements are implemented using software, the software may be stored in a computer-readable medium and loaded into the computing system using, for example, a removable storage drive. When executed by a processor in a computer system, the control module (in this embodiment, software instructions or executable computer program code) causes the processor to perform the functions of the invention as described herein.

Furthermore, the concepts of the present invention are applicable to any circuit for performing signal processing functions within a network element. It is further contemplated that, for example, a semiconductor manufacturer may employ the inventive concepts in designing a stand-alone device, such as a microcontroller of a Digital Signal Processor (DSP), an Application-Specific Integrated Circuit (ASIC), and/or any other subsystem component.

It will be appreciated that the above description, for clarity, describes embodiments of the invention with reference to a single processing logic. The inventive concept may, however, also be implemented by means of a number of different functional units and processors in order to provide signal processing functions. Hence, references to specific functional units are only to be seen as references to suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

Aspects of the invention may be implemented in any suitable form including hardware, software, firmware or any combination of these. The invention may optionally be implemented at least partly as computer software or as configurable modular components, such as FPGA devices, running on one or more data processors and/or digital signal processors. Thus, the elements and components of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way. Indeed the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units.

Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the invention is limited only by the attached claims. In addition, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the word "comprising" does not exclude the presence of other elements or steps.

Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor. Furthermore, although individual features may be included in different claims, these may possibly be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. Furthermore, the inclusion of a feature in one category of claims does not imply a limitation to this category but rather indicates that the feature is equally applicable to other claim categories as appropriate.

Furthermore, the order of features in the claims does not imply any specific order in which the features must be performed and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. Rather, the steps may be performed in any suitable order. Furthermore, singular references do not exclude a plurality. Thus, references to "a", "an", "first", "second", etc., do not preclude a plurality.

Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the invention is limited only by the attached claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term "comprising" or "comprises" does not exclude the presence of other elements.

Claims

1. A method for transmitting data from a base station to a user equipment based on a wireless cellular communication mobile network, comprising: transmitting a signal representing data from a base station to a user equipment over a radio link; receiving and storing the signal representative of data at the user equipment; after starting to transmit the signal representing the data, transmitting scheduling information from the base station to the user equipment, wherein the scheduling information is used for identifying resources used for transmitting the signal representing the data; receiving the scheduling information at the user equipment; recovering, at the user equipment, the data from the stored signal using the scheduling information.

2. The method of claim 1, wherein the scheduling information is transmitted after the transmission of the signal representing data is completed.

3. The method according to any of claims 1 or 2, wherein the scheduling information indicates an end of a data transmission signal, the data transmission signal being during transmission or after an end of a control transmission signal.

4. A method according to any of claims 1 or 2, wherein the signal representing data is transmitted in a data transmission region of a first time slot and the scheduling information is transmitted in a control region of a second time slot.

5. The method according to any of claims 1 or 2, wherein said signal representing data is transmitted on a physical downlink shared channel and said scheduling information is transmitted on a physical downlink control channel.

6. The method according to any of claims 1 or 2, wherein the scheduling information is sent in a downlink control information message.

7. A method according to any of claims 1 or 2, wherein the signal representing data is transmitted in a first time slot and the scheduling information is transmitted in a subsequent time slot.

8. The method of claim 7, wherein the scheduling information is transmitted in a time slot adjacent to the first time slot.

9. The method of claim 7, wherein the scheduling information is not transmitted in a time slot adjacent to the first time slot.

10. The method according to any of claims 1 or 2 or 8 or 9, wherein the scheduling information comprises an indication of time domain resources of a physical downlink shared channel, and wherein the row index of the resource utilization radio resource control configuration table comprises the signal representing data.

11. The method of claim 10, wherein other rows are configured in the radio resource control configuration table to indicate data transmitted before the scheduling information.

12. The method of any one of claims 1,2, 8, 9, or 11, further comprising: prior to transmitting the signal representing data, transmitting an indication to the user equipment that the data signal was received prior to scheduling information related to the data signal.

13. The method of claim 12, wherein the indication is a radio resource control message.

14. The method of claim 12, wherein the indication is sent based on an availability of control resources.

15. The method according to any of claims 13 or 14, wherein the indication is sent according to a class or type of the user equipment.

16. The method according to any of claims 13 or 14, wherein the indication is sent in the form of a broadcast message.

17. The method according to any of claims 13 or 14, wherein the indication is sent to a specific user equipment in the form of a message.

18. The method according to any of claims 13 or 14, wherein said indication further comprises an indication of a maximum delay between said signal representing data and said scheduling information.

19. The method of claim 18, wherein the maximum delay is indicated as a plurality of physical downlink control channel occasions.

20. The method according to any of claims 13 or 14 or 19, wherein the indication further comprises an indication of frequency resources used for data transmission prior to the relevant scheduling information.

21. A method for transmitting data from a base station to a user equipment based on a wireless cellular communication mobile network, comprising: transmitting a signal representing data from a base station to a user equipment over a radio link; after starting to transmit the signal representing the data, transmitting scheduling information from the base station to the user equipment, wherein the scheduling information is used for identifying resources used for transmitting the signal representing the data.

22. The method of claim 21, wherein the scheduling information indicates an end of a data transmission signal, and wherein the data transmission signal is during transmission or after the end of a control transmission signal.

23. The method according to any of claims 21 or 22, wherein said scheduling information is transmitted after completion of transmission of said signal representing data.

24. A method as claimed in any one of claims 21 or 22, wherein the signal indicative of data is transmitted in a data transmission region of a first time slot and the scheduling information is transmitted in a control region of a second time slot.

25. The method according to any of claims 21 or 22, wherein said signal representing data is transmitted on a physical downlink shared channel and said scheduling information is transmitted on a physical downlink control channel.

26. The method according to any of claims 21 or 22, characterised in that said scheduling information is sent in a downlink control information message.

27. A method according to any of claims 21 or 22, wherein the signal representing data is transmitted in a first time slot and the scheduling information is transmitted in a subsequent time slot.

28. The method of claim 27, wherein the scheduling information is transmitted in a time slot adjacent to the first time slot.

29. The method of claim 27, wherein the scheduling information is not transmitted in a time slot adjacent to the first time slot.

30. The method according to any of claims 21 or 22 or 28 or 29, wherein the indication comprises an indication of time domain resources of a physical downlink shared channel, and wherein the row index of the resource utilization radio resource control configuration table comprises the signal representing data.

31. The method of claim 30, wherein other rows are configured in the rrc configuration table to indicate data transmitted before the scheduling information.

32. The method of any one of claims 21, 22, 28, 29, or 31, further comprising: transmitting an indication to the user equipment prior to transmitting the signal representing data, the indication being to receive a data signal prior to scheduling information related to the data signal.

33. The method of claim 32, wherein the indication is a radio resource control message.

34. The method of claim 32, wherein the indication is sent based on an availability of control resources.

35. The method according to any of claims 33 or 34, wherein said indication is sent according to a class or type of said user equipment.

36. The method according to any of claims 33 or 34, wherein said indication is sent in the form of a broadcast message.

37. The method according to any of claims 33 or 34, wherein said indication is sent to a specific user equipment in the form of a message.

38. The method according to any of claims 33 or 34, wherein said indication further comprises an indication of a maximum delay between said signal representing data and said scheduling information.

39. The method of claim 38, wherein the maximum delay is indicated as a plurality of physical downlink control channel occasions.

40. The method according to any of claims 33 or 34 or 39, wherein the indication further comprises an indication of frequency resources used for data transmission prior to the relevant scheduling information.

41. A base station configured to perform the method of any of claims 21 to 40.

42. A method for transmitting data from a base station to a user equipment based on a wireless cellular communication mobile network, comprising: receiving and storing, at a user device, a signal representing data; after starting to transmit the signal representing the data, transmitting scheduling information from a base station to the user equipment, wherein the scheduling information is used for identifying resources used for transmitting the signal representing the data; receiving, at the user equipment, the scheduling information identifying the resources used for transmitting the signals representing data; recovering, at the user equipment, the data from the stored signal using the scheduling information.

43. The method of claim 42, wherein the scheduling information indicates an end of a data transmission signal, and wherein the data transmission signal is during transmission or after an end of a control transmission signal.

44. The method of claim 42, wherein the scheduling information is received after the reception of the signal representing data is completed.

45. A method according to any of claims 42 to 44, wherein the signal representing data is received in a data region of a first time slot and the scheduling information is received in a control region of a second time slot.

46. A method according to any of claims 42 to 44, wherein the signal representing data is received on a physical downlink shared channel and the scheduling information is received on a physical downlink control channel.

47. The method according to any of claims 42 to 44, wherein the scheduling information is received in a Downlink control information message.

48. A method as claimed in any of claims 42 to 44, wherein the signal representing data is received in a first time slot and the scheduling information is received in a subsequent time slot.

49. The method of claim 48, wherein the scheduling information is received in a time slot adjacent to the first time slot.

50. The method of claim 48, wherein the scheduling information is not received in a time slot adjacent to the first time slot.

51. The method according to any of claims 42 or 43 or 44 or 49 or 50, wherein the indication comprises an indication of time domain resources of a physical downlink shared channel, and wherein the row index of the resource utilization radio resource control configuration table comprises the signal representing data.

52. The method of claim 51, wherein other rows are configured in the RRC configuration table to indicate data transmitted before the scheduling information.

53. The method of any one of claims 42, 43, 44, 49, 50, or 52, further comprising: receiving an indication prior to receiving the signal representing data, the indication being that the data signal was received prior to scheduling information related to the data signal.

54. The method of claim 53, wherein the indication is a radio resource control message.

55. The method of claim 53, wherein the indication is received in a broadcast message.

56. The method according to any of claims 54 or 55, characterised in that the indication is received in the form of a message to a specific user equipment.

57. The method of any of claims 54 or 55, wherein the indication further comprises an indication of a maximum delay between the signal representative of data and the scheduling information.

58. The method of claim 57, wherein the maximum delay is indicated as a plurality of physical downlink control channel occasions.

59. The method according to any of claims 54 or 55 or 58, wherein said indication further comprises an indication of frequency resources on which said signal representing data is received prior to receiving relevant scheduling information.

60. The method according to any of claims 54 or 55 or 58, wherein the user equipment stores the signal representing data for at least the indicated maximum delay.

61. A user equipment configured to perform the method of any of claims 42 to 60.