WO2020030029A1

WO2020030029A1 - Enhancements of Automatic Repetition in a Wireless Communication Network

Info

Publication number: WO2020030029A1
Application number: PCT/CN2019/099716
Authority: WO
Inventors: Guang Liu; Efstathios KATRANARAS
Original assignee: JRD Communication (Shenzhen) Ltd.
Priority date: 2018-08-10
Filing date: 2019-08-08
Publication date: 2020-02-13
Also published as: GB201813109D0; CN112352392A

Abstract

An enhancement of automatic repetition in a wireless communication network is provided as a method of managing transmission time resource assignment during automatic repetition of data transmission from a wireless base station to a wireless device in a wireless communication network, comprising the steps of: generating in the wireless base station control information which controls data transmission from the wireless base station to the wireless device, modifying the control information to include at least a first transmission time resource assignment field defining a first transmission time pattern for the data transmission and a second transmission time resource assignment field defining a second transmission time pattern for the data transmission, and transmitting the modified control information from the wireless base station to the wireless device and transmitting data from the wireless base station to the wireless device in accordance with the at least first and second transmission time patterns of the modified control information. Further enhancements are provided in methods of indicating control information repetition during automatic repetition of control information and data transmission from a wireless base station to a wireless device in a wireless communication network, controlling automatic repetition of data transmission from a wireless base station to a wireless device in a wireless communication network. The invention further provides a wireless base station and a wireless device configured to perform any of the methods described above.

Description

Enhancements of Automatic Repetition in a Wireless Communication Network

Technical Field

The following disclosure relates to communication of data in a wireless network and more specifically to enhancements of automatic repetition data transmission and/or control information to improve data reliability and reduce latency.

Background

Wireless communication systems, such as the third-generation (3G) of mobile telephone standards and technology are well known. Such 3G standards and technology have been developed by the Third Generation Partnership Project (3GPP) . The 3rd generation of wireless communications has generally been developed to support macro-cell mobile phone communications. Communication systems and networks have developed towards a broadband and mobile system.

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

The 3rd Generation Partnership Project has developed the so-called Long Term Evolution (LTE) system, namely, an Evolved Universal Mobile Telecommunication System Territorial Radio Access Network, (E-UTRAN) , for a mobile access network where one or more macro-cells are supported by a base station known as an eNodeB or eNB (evolved NodeB) . More recently, LTE is evolving further towards the so-called 5G or NR (new radio) systems where one or more cells are supported by a base station known as a gNB. NR is proposed to utilise an Orthogonal Frequency Division Multiplexed (OFDM) physical transmission format.

A trend in wireless communications is towards the provision of lower latency and higher reliability services. For example, NR is intended to support Ultra-reliable and low-latency communications (URLLC) and massive Machine-Type Communications (mMTC) which are intended to provide low latency and high reliability for small packet sizes (typically 32 bytes) . A user-plane latency of 1ms has been proposed with a reliability of 99.99999%, and at the physical layer a packet loss rate of 10 ^-5 or 10 ^-6 has been proposed.

For URLLC, higher data reliability (up to 10 ^-6 level) , higher availability, time synchronization down to the order of a few μs where the value can be 1 or a few μs depending on the frequency range, short latency in the order of 0.5 to 1 ms, depending on the use cases (factory automation, transport industry and electrical power distribution) are required.

To achieve the required reliability and latency, there are basically two types of scheduling schemes. One is Hybrid Automatic Repeat Request (HARQ) based retransmission of data and the other is automatic repetition of data transmission. Common understanding about these two solutions is that the HARQ based retransmission is more resource efficient but has longer latency while the automatic repetition has opposite characteristics.

Figure 1 illustrates HARQ based retransmission of data between a Next Generation Node B (gNB) and a UE. After Downlink Control Information (DCI) is received by the UE on a Physical Downlink Control Channel (PDCCH) and data is received by the UE on a Physical Downlink Shared Channel (PDSCH) , there is a processing gap at the UE side which is 1 Transmitter Time Interval (TTI) minimum. If the DCI is received correctly by the UE but the data is not correctly received, the UE will indicate a Negative Acknowledgement (NACK) to the gNB via a Physical Uplink Control Channel (PUCCH) . When a NACK is received, the gNB will schedule a retransmission of the DCI and data to the UE, in the same way as the initial transmission, and the UE can combine the two data receptions before decoding.

Figure 2 illustrates automatic repetition of data transmission between a gNB and a UE. DCI is sent from the gNB to the UE on a PDCCH. After data on a first PDSCH is sent to the UE, the gNB will automatically repeat the data transmission on at least a second PDSCH. The UE may try to decode the data received on the first PDSCH and, if not successful, decode the combination of data received on both PDSCHs. The number of automatic repetitions is configured in an upper layer message of the gNB. There may or may not be ACK/NACK feedback during or after the repetitions.

If the data is correctly obtained, it will be delivered to an upper layer of the UE. The Downlink (DL) latency is defined as the time between a data packet being received from the upper layer of the gNB and the data packet being delivered to the upper layer of the UE.

Assuming a 30 kHz Sub Carrier Spacing (SCS) and a 4 OFDM symbol (OS) TTI, the maximum latency of the HARQ based retransmission is 0.93 ms after 1 retransmission, while it is only about 0.64 ms for automatic repetition with 1 repetition. The number of resources used by the automatic repetition is nearly twice of the HARQ based retransmission for which the retransmission happens only when the data on the first PDSCH is not successfully received. This example confirms the advantages and disadvantages of both schemes as mentioned above. There is therefore a requirement for enhancements of the automatic repetition scheduling scheme to improve efficiency, reliability and latency.

Summary

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 subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

A method is provided of managing transmission time resource assignment during automatic repetition of data transmission from a wireless base station to a wireless device in a wireless communication network, comprising the steps of: generating in the wireless base station control information which controls data transmission from the wireless base station to the wireless device, modifying the control information to include at least a first transmission time resource assignment field defining a first transmission time pattern for the data transmission and a second transmission time resource assignment field defining a second transmission time pattern for the data transmission, and transmitting the modified control information from the wireless base station to the wireless device and transmitting data from the wireless base station to the wireless device in accordance with the at least first and second transmission time patterns of the modified control information.

The first and second transmission time patterns may each comprise a position, a length and a repetition value of at least one transmission time for the data transmission.

The position of the transmission time may be described by: an offset value defining a number of Time Transmission Intervals between start positions of the data transmission time and the control information transmission time and a location value defining a number of OFDM symbols between a start OFDM symbol of the Time Transmission Interval and a start OFDM symbol of the data transmission time.

The length of the transmission time may comprise at least one OFDM symbol of a Time Transmission Interval.

The repetition value of the transmission time may be contained in an automatic repetition parameter in the control information.

The automatic repetition parameter may be aggregationFactorDL.

A method is provided of managing transmission time resource assignment during automatic repetition of data transmission from a wireless base station to a wireless device, comprising the steps of: generating, in the wireless base station, an indication whether an existing time transmission resource assignment for the wireless device can be extended to include a time transmission resource assignment for control information when no control information is transmitted to the wireless device, and transmitting the indication from the wireless base station to the wireless device and transmitting data from the wireless base station to the wireless device in accordance with the indication.

The indication may be configured by an upper layer message of the wireless base station.

The indication may be included in the control information.

The indication may include an ON/OFF flag.

The indication may include a starting position in TTI from where the extension should be applied.

A method is provided of indicating control information repetition during automatic repetition of control information and data transmission from a wireless base station to a wireless device in a wireless communication network, comprising the steps of: generating in the wireless base station control information which includes a control information repetition index having a value which indicates a first control information transmission, transmitting the control information from the wireless base station to the wireless device, generating in the wireless base station control information which includes a control information repetition index having a value which indicates a second control information transmission, transmitting the control information from the wireless base station to the wireless device, and repeating the steps of generation of the control information and transmission of the control information for a pre-defined number of control information transmissions.

The control information repetition index may be 0 for the first control information transmission, 1 for the second control information transmission up to the pre-defined number of control information transmissions -1 for a final control information transmission.

The method may fur comprise in the wireless device using the control information repetition index to determine a number of remaining data transmissions by: receiving a control information transmission, determining a current value of the control information repetition index from the control information transmission, determining a value of a data transmission repetition number from the control information transmission, and determining the number of remaining data transmissions by subtracting the current value of the control information repetition index from the value of a data transmission repetition number.

A method is provided of controlling automatic repetition of data transmission from a wireless base station to a wireless device in a wireless communication network, comprising the steps of: commencing in the wireless device decoding of a transmission block of the data transmission before receipt of a whole of the transmission block, continuing decoding of the transmission block of data until all of the transmission block is correctly received, sending an acknowledge of receipt of the transmission block from the wireless device to the wireless base station, and detecting receipt of the acknowledgement in the wireless base station and terminating automatic repetition of the data transmission from the wireless base station to the wireless device.

Commencing in the wireless device decoding of a transmission block of the data transmission before receipt of the whole of the transmission block may comprise mapping of resource elements by the wireless device in the order of frequency and then time.

Sending an acknowledge of receipt of the transmission block from the wireless device to the wireless base station may comprise using at least one Physical Uplink Control Channel pre-configured with a sequence indicating the acknowledgement.

Sending an acknowledge of receipt of the transmission block from the wireless device to the wireless base station may comprise using a resource of the at least one Physical Uplink Control Channel overlapped with a resource of at least one Physical Uplink Shared Channel of another wireless device.

Detecting receipt of the acknowledgement in the wireless base station may comprise monitoring the at least one pre-configured Physical Uplink Control Channel and blind detection of the sequence indicating the acknowledgement.

A method is provided of controlling automatic repetition of data transmission from a wireless base station to a wireless device in a wireless communication network, comprising the steps of: generating in the wireless base station control information which controls data transmission from the wireless base station to the wireless device, modifying the control information to include an automatic repetition field having at least one value defining a number of data transmission repetitions, and transmitting the modified control information from the wireless base station to the wireless device and transmitting data from the wireless base station to the wireless device in accordance with the modified control information.

The automatic repetition field may comprise at least one repetition flag bit having a value of one of : a first value equal to 1 which deactivates data transmission repetition; a second value greater than 1 which activates data transmission repetition and indicates the number of data transmission repetitions.

The automatic repetition field may comprise a repetition parameter having a value of one of : a first value equal to 1 which deactivates data transmission repetition; a second value greater than 1 which activates data transmission repetition and indicates the number of data transmission repetitions.

The repetition parameter may be an aggregationFactorDL repetition parameter.

The method may further comprise configuring the automatic repetition field to have two or more values each defining the number of data transmission repetitions and modifying a repetition parameter of an upper layer message of the wireless base station to select one of the values of the automatic repetition field.

The selected value of the automatic repetition field may have a value of one of: a first value equal to 1 which deactivates data transmission repetition; a second value greater than 1 which activates data transmission repetition and indicates the number of data transmission repetitions.

In the methods described above, the control information generated by the base station may be in the form of Downlink Control Information.

In the methods described above, the modified control information may be transmitted from the wireless base station to the wireless device on a Physical Downlink Control Channel.

In the methods described above, the data may be transmitted from the wireless base station to the wireless device on at least one Physical Downlink Shared Channel.

In the methods described above, the wireless communication network may be a New Radio network supporting Ultra-Reliable and Low-Latency Communications, the wireless base station may be a Next Generation Node B base station and the wireless device may be a User Equipment.

A wireless base station is provided configured to perform any of the methods described above.

A wireless device configured to perform any of the methods described above.

Brief description of the drawings

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

Figure 1 shows HARQ based retransmission of data;

Figure 2 shows automatic repetition of data transmission;

Figure 3 shows a schematic diagram of a cellular network;

Figure 4 shows legacy transmission time resource assignment during automatic repetition of data transmission;

Figure 5 shows two examples of first and second transmission time patterns used in transmission time resource assignment during automatic repetition of data transmission;

Figure 6 shows legacy automatic repetition of control information transmission with and without automatic repetition of data transmission;

Figure 7 shows controlling of automatic repetition of data transmission, and

Figure 8 shows control information and data transmission which uses HARQ based retransmission for the initial transmission of the control information and data and uses automatic repetition for further data transmissions.

Detailed description of the preferred embodiments

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

Figure 3 shows a schematic diagram of three base stations (for example, eNBs or gNBs depending on the particular cellular standard and terminology) forming a cellular network. Typically, each of the base stations will be deployed by one cellular network operator to provide geographic coverage for UEs in its area. The base stations form a Radio Area Network (RAN) . Each base station provides wireless coverage for UEs in its area or cell. The base stations are interconnected via a X2 interface and are connected to a core network via a S1 interface. As will be appreciated only basic details are shown for the purposes of exemplifying the key features of a cellular network.

The base stations each comprise hardware and software to implement the RAN's functionality, including communications with the core network and other base stations, carriage of control and data signals between the core network and UEs, and maintaining wireless communications with UEs associated with each base station. The core network comprises hardware and software to implement the network functionality, such as overall network management and control, and routing of calls and data.

Although not shown in detail any of the devices or apparatus that form part of the network may include at least a processor, a storage unit and a communications interface, wherein the processor unit, storage unit, and communications interface are configured to perform the method of any aspect of the present invention. Further options and choices are described below.

In a network such as that illustrated in Figure 3, the standards currently dictate that each automatic repetition of data transmission has the same transmission time resource assignment. An example of this is illustrated in Figure 4. In a 2 OFDM symbol TTI network, in legacy automatic repetition transmission time resource assignment, the first OFDM symbol of the first TTI is used by a PDCCH for the DCI and the second OFDM symbol of the first TTI is used by a PDSCH for data transmission. The automatic repetition parameter, aggregationFactorDL, in the DCI is equal to 3, so the second OFDM symbol of the second TTI is used by a PDSCH for the first automatic repetition of data transmission, and the second OFDM symbol of the third TTI is used by a PDSCH for the second automatic repetition of data transmission, in total 3 transmissions. Since the same time transmission assignment is used for all of the automatic repetitions, the first OFDM symbol in each TTI is not used and it is very difficult to schedule this resource to another UE.

A method is provided of managing transmission time resource assignment during automatic repetition of data transmission from a gNB to a UE in a wireless communication network, such as a NR network supporting URLLC. This comprises generating, in the gNB, a DCI which controls data transmission from the gNB to the UE and modifying the DCI to include at least a first transmission time resource assignment field defining a first transmission time pattern for the data transmission and a second transmission time resource assignment field defining a second transmission time pattern for the data transmission. The modified DCI is then transmitted from the gNB to the UE on a PDCCH and data is transmitted from the gNB to the UE on a PDSCH in accordance with the at least first and second transmission time patterns of the modified DCI.

The first and second transmission time patterns each comprise a position, a length and a repetition value of at least one transmission time for the data transmission. The position of the transmission time is described by an offset value defining a number of Time Transmission Intervals between start positions of the data transmission time and the DCI transmission time and a location value defining a number of OFDM symbols between a start OFDM symbol of the TTI and a start OFDM symbol of the data transmission time.

The length of the transmission time comprises at least one OFDM symbol of a Time Transmission Interval. The repetition value of the transmission time is contained in the automatic repetition parameter, aggregationFactorDL, received from either the DCI or an upper layer message.

Referring to Figure 5, two examples of first and second transmission time patterns are illustrated. In each example, the first pattern is shown in deep grey and the second pattern is shown in light grey. Each example illustrates use of all the second OFDM symbols in each TTI.

In the first example, the first transmission time pattern has a position of each transmission time for the data transmission described by an offset value K ₀=0 (i.e. in the same TTI as DCI) and a location value comprising an OFDM symbol S=1. The length of each transmission time for the data transmission is one OFDM symbol L=1 of a Time Transmission Interval. The repetition value of the transmission time, received from either the DCI or an upper layer message of the gNB, is 2. The second transmission time pattern has a position of each transmission time for the data transmission described by an offset value K ₀=1 and a location value comprising an OFDM symbol S=0. The length of each transmission time for the data transmission is one OFDM symbol L=1 of a Time Transmission Interval and the repetition value of the transmission time, received from either the DCI or an upper layer message of the gNB, is 1. It can be seen that use of these two patterns together results in use of all the second OFDM symbols in each TTI.

In the second example, the first transmission time pattern has a position of each transmission time for the data transmission described by an offset value K ₀=0 (i.e. in the same TTI as DCI) and a location value comprising an OFDM symbol S=1. The length of each transmission time for the data transmission is one OFDM symbol L=1 of a Time Transmission Interval. The repetition value of the transmission time, received from either the DCI or an upper layer message of the gNB, is 1. The second transmission time pattern has a position of each transmission time for the data transmission described by an offset value K ₀=1 and a location value comprising an OFDM symbol S=0. The length of each transmission time for the data transmission is one OFDM symbol L=2 of a Time Transmission Interval and the repetition value of the transmission time, received from either the DCI or an upper layer message of the gNB, is 1. It can be seen that use of these two patterns together also results in use of all the second OFDM symbols in each TTI.

An alternative method is provided of managing transmission time resource assignment during automatic repetition of data transmission from a gNB to a UE. This comprises generating, in the gNB, an indication whether an existing time transmission resource assignment for the UE can be extended to include a time transmission resource assignment for the DCI when no DCI is transmitted to the UE. The indication is transmitted from the gNB to the UE and the data is transmitted from the gNB to the UE in accordance with the indication.

The existing time transmission resource assignment for the UE is the resource block (RB) allocation for the UE specified by one or more OFDM symbols in the PDSCH. The time transmission resource assignment for the DCI is the TB allocation for the DCI specified by one or more OFDM symbols in the PDCCH.

The indication can be configured by an upper layer message of the gNB or included in the DCI. The indication can include an ON/OFF flag and/or a starting position, in TTI, from where the extension should be applied.

Simply, but less flexibly, the UE can be configured to extend its RB allocation automatically into the DCI OFDM symbol allocation when it can be confirmed that there is no DCI for the UE in the TTI. Additionally, a starting position can be indicated in the DCI to indicate from which TTI the automatic extension shall start.

In a network such as that illustrated in Figure 3, in some legacy transmission protocols, the DCI is sent from the gNB to the UE on a PDCCH only once (see Figure 6) . As the DCI comprises the information required by the UE to decode the data received from the gNB, when the DCI is lost, the data and all repetitions of the data cannot be decoded.

In other legacy transmission protocols, the DCI is repeatedly sent from the gNB to the UE on repeated PDCCH (see Figure 6) . When the first DCI is lost and the second DCI is received, the UE does not know if the received DCI is the first DCI or a repeated DCI. As a result, the UE does not know if there has been a previous data transmission and if it can perform soft combining of the current data transmission with a previous data transmission. One option for the UE is to attempt to decode the current data transmission assuming it is the first transmission. If this is not successful, the UE attempts to decode the current data transmission by assuming it is the second transmission. If this is successful, soft combining of the first and second data transmissions can be done. The drawback of this option is that it increases the number of blind decoding and accordingly increases the UE complexity. An additional problem when the first DCI or more than one DCI is lost is the UE may carry out incorrect soft combining by including data transmissions of other UE (s) which will pollute the soft buffer and cause packet loss in the UE.

A method is provided of indicating DCI repetition during automatic repetition of DCI and data transmission from a gNB to a UE in a wireless communication network, such as a NR network supporting URLLC. This comprises generating, in the gNB, DCI which includes a control information repetition index having a value which indicates a first DCI transmission, transmitting the DCI from the gNB to the UE, generating, in the gNB, DCI which includes a control information repetition index having a value which indicates a second DCI transmission, transmitting the DCI from the gNB to the UE, and repeating generation of the DCI and transmission of the DCI for a pre-defined number of DCI transmissions.

The control information repetition index can comprise at least one flag bit and may have a value of 0 for the first control information transmission, 1 for the second control information transmission up to the pre-defined number of control information transmissions -1 for a final control information transmission.

The method further comprises, in the UE, using the control information repetition index to determine a number of remaining data transmissions by receiving a DCI transmission, determining a current value of the control information repetition index from the DCI transmission, determining a value of a data transmission repetition number from the DCI transmission, and determining the number of remaining data transmissions by subtracting the current value of the control information repetition index from the value of a data transmission repetition number.

The control information is transmitted from the gNB to the UE on a PDCCH and the data is transmitted from the gNB to the UE on at least one PDSCH.

Use of a control information repetition index in the DCI enables the UE, on receipt of a DCI, to know whether the DCI is a first, second, etc. DCI transmission. The UE can then know if there has been a previous data transmission and if it can perform soft combining of a current data transmission with a previous data transmission. Use of a control information repetition index in the DCI enables early blind detection with soft combining with improved reliability and latency and additionally, it can help to reduce the standardization effort when the LTE URLLC scheme for DCI repetition on PDSCH is to be used in NR.

Use of a control information repetition index in the DCI to determine a number of remaining data transmissions enables the UE to avoid incorrect soft combining of data transmissions of other UE (s) .

For LTE URLLC, a parameter, repetition number, is included in the DCI to indicate the number of data transmissions in the current transmission bundle. In LTE DCI format 7-1A, 2 bits are used for this parameter to indicate a number from {1, 2, 3, a configurable number} for the number of data transmission repetitions (including the initial transmission) , where the last value is upper layer configurable. With DCI repetition supported, it could be considered to use this parameter to indicate the number of “remaining repetitions” of data transmission in the bundle. In the example of Figure 6Error! Reference source not found., the first DCI will indicate there are 3 remaining data transmission repetitions while the second DCI will indicate there are 2 remaining data transmission repetitions. When only the second DCI is received (the first one is lost) , the UE knows that 2 data transmissions should be combined. This prevents the UE from combining a third data transmission from a different UE.

A problem exists for this option. When the data transmission totals 5 transmissions and the DCI transmission totals 2 transmissions, the value of the repetition number parameter in the first DCI is 5 and, accordingly, in the second DCI its value should be 4. However, 4 is not an available value in the list for this parameter, so 4 cannot be indicated. To solve this problem, the parameter list is extended to include each value between the minimum and the maximum number of data transmissions. More than 2 bits in the DCI will be required for the extended parameter. The proposed DCI repetition index avoids extending the repetition number parameter list.

It is a well-known problem of communication networks operating automatic repetition of data transmission from a gNB to a UE, that all configured data repetitions are to be transmitted to the UE even when the UE has received the data successfully in the first transmission. Early termination can be used in a number of cases when the number of repetitions is big. When the number of repetitions is small, early termination cannot really benefit the resource efficiency due to the long latency of feedback. A solution is proposed to reduce the early termination latency so that it can be used by automatic repetition with a smaller number of repetitions.

A method is provided of controlling automatic repetition of data transmission from a gNB to a UE in a wireless communication network. This comprises commencing, in the UE, decoding of a transmission block of the data transmission before receipt of a whole of the transmission block, continuing decoding of the transmission block of data until all of the transmission block is received, sending an acknowledge of receipt of the transmission block from the UE to the gNB, and detecting receipt of the acknowledgement in the gNB and terminating automatic repetition of the data transmission from the gNB to the UE.

Commencing, in the UE, decoding of a transmission block of the data transmission before receipt of the whole of the transmission block comprises mapping of resource elements by the UE in the order of frequency and then time.

Sending an acknowledge of receipt of the transmission block from the UE to the gNB comprises using at least one PUCCH pre-configured with a sequence indicating the acknowledgement. Detecting receipt of the acknowledgement in the gNB comprises monitoring the at least one pre-configured PUCCH and blind detection of the sequence indicating the acknowledgement. A resource of the at least one PUCCH may be overlapped with a resource of at least one PUSCH of another UE.

The method is illustrated in Figure 7, which shows automatic repetition of data transmission from a gNB to a UE in a wireless communication network in which each TTI has 7 OFDM symbols, 1 for the DCI and 6 for data transmission on one or more PDSCHs. The data is configured to transmit 3 times in total. It is possible for the UE to start decoding a TB before the end of receipt of the TB i.e. before the end of a TTI. Theoretically the TB is decodable after the first OFDM symbol of the data for a code rate less than 1/18 or after the second OFDM symbol of the data for a code rate less than 1/9. A number of selected PUCCH resources can be configured as shown.

Enabling early decoding before the end of receipt of a TB reduces the early termination feedback latency. Configuring multiple PUCCH resources per TTI increases the number of PUCCH ACK transmission chances, reduces the ACK false alarm rate and avoids adding too much complexity to the gNB. An ACK only feedback can then be used. Overlapping the PUCCH resource with PUSCH resource of a different will simplify the PUSCH resource scheduling significantly.

In a network such as that illustrated in Figure 3, the standards currently dictate that the number of automatic repetitions of data transmission from a gNB to a UE is included in an upper layer message of the gNB and, once it is configured, it cannot be changed dynamically. Every time data is received by the UE on a scheduled PDSCH, the UE will assume that the data is to be followed by a fixed number of automatic repetitions as configured in the gNB upper layer message and it is not possible for the gNB to schedule data transmission with or without automatic repetition dynamically.

The gNB may want to use HARQ based retransmission for the initial data transmission to the UE for better efficiency and use automatic repetition for further data transmissions to the UE for a shorter latency. This cannot be supported by the gNB with the existing standards, as once the number of automatic repetitions of data transmission in the upper layer message of the gNB is configured, this number of repetitions of data transmission has to be sent to the UE.

A method is provided of controlling automatic repetition of data transmission from a gNB to a UE in a wireless communication network, such as a NR network supporting URLLC. This comprises generating, in the gNB, the DCI which controls data transmission from the gNB to the UE and modifying the DCI to include an automatic repetition field having at least one value defining a number of data transmission repetitions. The modified DCI is then transmitted to the UE on a PDCCH and data is transmitted from the gNB to the UE on a PDSCH in accordance with the modified DCI. If the number of data transmission repetitions is equal to 1, the automatic repetition is inactive, and no further repetition (s) of data will be transmitted after the first data transmission. If the number of data transmission repetitions is greater than 1, the automatic repetition is active, and the number of automatic repetitions of data as configured will be transmitted.

The automatic repetition field may comprise at least one repetition flag bit having a value of one of : a first value equal to 1 which deactivates data transmission repetition; a second value greater than 1 which activates data transmission repetition and indicates the number of data transmission repetitions. For example, the repetition flag bit may have a value of either 0 which deactivates data transmission repetition or 1 which activates data transmission repetition.

The automatic repetition field may comprise a repetition parameter, e.g. aggregationFactorDL. This parameter has a value of either a first value equal to 1 which deactivates data transmission repetition or a second value greater than 1 which activates data transmission repetition and indicates the number of automatic repetitions.

The modified DCI, containing the automatic repetition field comprising the aggregationFactorDL repetition parameter, is received by the UE. When the aggregationFactorDL repetition parameter = 1, this informs the UE that there is no further automatic repetition after the first data transmission. When the aggregationFactorDL repetition parameter > 1 this informs the UE that there are aggregationFactorDL -1 automatic repetition (s) after the first data transmission.

The selected value may have a value equal to 1 to deactivate automatic repetition of data transmission or a value greater than 1 to activate automatic repetition of data transmission and indicate the number of automatic repetitions. If more than two values for the automatic repetition field are added to the DCI, the gNB will have more flexibility in the scheduling of data transmission to the UE.

The method of controlling automatic repetition of data transmission from a gNB to a UE allows a network to employ a combined solution of HARQ based retransmission and automatic repletion to achieve benefits in efficiency and latency from both. Figure 8 illustrates transmission from a gNB to a UE which uses HARQ based retransmission for the initial transmission of the DCI and data providing increased efficiency and uses automatic repetition for further transmissions providing decreased latency.

Any two or more of the above-described enhancements of automatic repetition in communication networks can be combined. For example, the enhancements can be combined as follows.

A parameter of the number of data transmission repetitions, N _d, is configured by an upper layer message of the gNB, and a flag bit is included in the DCI to indicate if the parameter is activated or not. If it is not activated, there is only one transmission for the data scheduled by the DCI on the PDSCH, otherwise the data is transmitted repeatedly on the PDSCH as defined by the parameter. (Alternatively, this parameter can be included in DCI, just like LTE URLLC, and in this case, this enhancement is bypassed but the following combination is still applicable. ) At the same time, the number of DCI transmission repetitions, N _c, is also configured by an upper layer message of the gNB. This indicates to the UE how many times the DCI transmission will be repeated in total. A DCI repetition index is included in the DCI, i.e., I _c, = 0, 1…N _c-1.

In the example, where N _d = 5 and N _c = 2, I _c, = 0 in the first DCI, and I _c, = 1 in the second DCI. If the first DCI is lost and the second DCI is received, the UE knows that:

1) This is the second repetition of DCI from N _c = 2 and I _c, = 1, and there is an old transmission in the last TTI which can be used for soft combining of PDSCH;

2) There are still 4 remaining transmissions of the data on the PDSCH (including the current one) from N _d = 5 and I _c, = 1, so transmissions from, at most, 4 future TTIs can be combined;

3) There is no DCI in all remaining TTIs from the next TTI from N _c = 2 and I _c, = 1, and if it is configured, the UE transmission time resource assignment can be extended to the DCI transmission time resource assignment automatically with the same transmission frequency resource assignment in all the TTIs;

4) Multiple PUCCH resources are configured for the repetition bundle and these resources overlap with PUSCH resources of one or more other UEs. Once the data on the PDSCH is decoded successfully before the end of the bundle, a PUCCH is indicated to the gNB.

The signal processing and transmission functionality of the embodiments of the invention especially the gNB and the UE may be achieved using computing systems or architectures known to those who are skilled in the relevant art. Computing systems such as a desktop, laptop or notebook computer, hand-held computing device (PDA, cell phone, palmtop, etc. ) , mainframe, server, client, or any other type of special or general purpose computing device as may be desirable or appropriate for a given application or environment can be used. The computing system can include one or more processors which can be implemented using a general or special-purpose processing engine such as, for example, a microprocessor, microcontroller or other control module.

The computing system can also include a main memory, such as random access memory (RAM) or other dynamic memory, for storing information and instructions to be executed by a processor. Such a main memory also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by the processor. The computing system may likewise include a read only memory (ROM) or other static storage device for storing static information and instructions for a processor.

The computing system may also include an information storage system which 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) read or write drive (R or RW) , or other removable or fixed media drive. 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 media drive. The storage media may include a computer-readable storage medium having particular computer software or data stored therein.

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

The computing system can also include a communications interface. Such a communications interface can be used to allow software and data to be transferred between a computing system and external devices. Examples of communications interfaces can include a modem, a network interface (such as an Ethernet or other NIC card) , a communications port (such as for example, a universal serial bus (USB) port) , a PCMCIA slot and card, etc. Software and data transferred via a communications interface are in the form of signals which can be electronic, electromagnetic, and optical or other signals capable of being received by a 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, for example, a memory, storage device, or storage unit. These and other forms of computer-readable media may store one or more instructions for use by the processor comprising the 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 a 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.

The non-transitory computer readable medium may comprise at least one from a group consisting of: a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a Read Only Memory, a Programmable Read Only Memory, an Erasable Programmable Read Only Memory, EPROM, an Electrically Erasable Programmable Read Only Memory and a Flash memory. In an embodiment where the elements are implemented using software, the software may be stored in a computer-readable medium and loaded into computing system using, for example, removable storage drive. A control module (in this example, software instructions or executable computer program code) , when executed by the processor in the computer system, causes a processor to perform the functions of the invention as described herein.

Furthermore, the inventive concept can be applied to any circuit for performing signal processing functionality within a network element. It is further envisaged that, for example, a semiconductor manufacturer may employ the inventive concept in a design of a stand-alone device, such as a microcontroller of a digital signal processor (DSP) , or application-specific integrated circuit (ASIC) and/or any other sub-system element.

It will be appreciated that, for clarity purposes, the above description has described embodiments of the invention with reference to a single processing logic. However, the inventive concept may equally be implemented by way of a plurality of different functional units and processors to provide the signal processing functionality. Thus, 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 organisation.

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 running on one or more data processors and/or digital signal processors or configurable module components such as FPGA devices.

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 present invention is limited only by the accompanying claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognise that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term ‘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, for example, a single unit or processor. Additionally, 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. Also, 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. In addition, 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 present invention is limited only by the accompanying claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognise that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term ‘comprising’ or “including” does not exclude the presence of other elements.

Claims

A method of managing transmission time resource assignment during automatic repetition of data transmission from a wireless base station to a wireless device in a wireless communication network, comprising the steps of:

generating in the wireless base station control information which controls data transmission from the wireless base station to the wireless device,

modifying the control information to include at least a first transmission time resource assignment field defining a first transmission time pattern for the data transmission and a second transmission time resource assignment field defining a second transmission time pattern for the data transmission, and

transmitting the modified control information from the wireless base station to the wireless device and transmitting data from the wireless base station to the wireless device in accordance with the at least first and second transmission time patterns of the modified control information.
A method according to claim 1 wherein the first and second transmission time patterns each comprise a position, a length and a repetition value of at least one transmission time for the data transmission.
A method according to claim 2 wherein the position of the transmission time is described by:

an offset value defining a number of Time Transmission Intervals between start positions of the data transmission time and the control information transmission time and

a location value defining a number of OFDM symbols between a start OFDM symbol of the Time Transmission Interval and a start OFDM symbol of the data transmission time.
A method according to claim 2 wherein the length of the transmission time comprises at least one OFDM symbol of a Time Transmission Interval.
A method according to claim 2 wherein the repetition value of the transmission time is contained in an automatic repetition parameter in the control information.
A method according to claim 5 wherein the automatic repetition parameter is aggregationFactorDL.
A method of managing transmission time resource assignment during automatic repetition of data transmission from a wireless base station to a wireless device, comprising the steps of:

generating, in the wireless base station, an indication whether an existing time transmission resource assignment for the wireless device can be extended to include a time transmission resource assignment for control information when no control information is transmitted to the wireless device, and

transmitting the indication from the wireless base station to the wireless device and transmitting data from the wireless base station to the wireless device in accordance with the indication.
A method according to claim 7 wherein the indication is configured by an upper layer message of the wireless base station.
A method according to claim 7 wherein the indication is included in the control information.
A method according to any one of claims 7 to 9 wherein the indication includes an ON/OFF flag.
A method according to any one of claims 7 to 10 wherein the indication includes a starting position in TTI from where the extension should be applied.
A method of indicating control information repetition during automatic repetition of control information and data transmission from a wireless base station to a wireless device in a wireless communication network, comprising the steps of:

generating in the wireless base station control information which includes a control information repetition index having a value which indicates a first control information transmission,

transmitting the control information from the wireless base station to the wireless device,

generating in the wireless base station control information which includes a control information repetition index having a value which indicates a second control information transmission,

transmitting the control information from the wireless base station to the wireless device, and

repeating the steps of generation of the control information and transmission of the control information for a pre-defined number of control information transmissions.
A method according to claim 12 wherein the value of the control information repetition index is 0 for the first control information transmission, 1 for the second control information transmission up to the pre-defined number of control information transmissions -1 for a final control information transmission.
A method according to claim 12 or claim 13 further comprising in the wireless device using the control information repetition index to determine a number of remaining data transmissions by:

receiving a control information transmission,

determining a current value of the control information repetition index from the control information transmission,

determining a value of a data transmission repetition number from the control information transmission, and

determining the number of remaining data transmissions by subtracting the current value of the control information repetition index from the value of a data transmission repetition number.
A method of controlling automatic repetition of data transmission from a wireless base station to a wireless device in a wireless communication network, comprising the steps of:

commencing in the wireless device decoding of a transmission block of the data transmission before receipt of a whole of the transmission block,

continuing decoding of the transmission block of data until all of the transmission block is correctly received,

sending an acknowledge of receipt of the transmission block from the wireless device to the wireless base station, and

detecting receipt of the acknowledgement in the wireless base station and terminating automatic repetition of the data transmission from the wireless base station to the wireless device.
A method according to claim 15 wherein commencing in the wireless device decoding of a transmission block of the data transmission before receipt of the whole of the transmission block comprises mapping of resource elements by the wireless device in the order of frequency and then time.
A method according to claim 15 or claim 16 wherein sending an acknowledge of receipt of the transmission block from the wireless device to the wireless base station comprises using at least one Physical Uplink Control Channel pre-configured with a sequence indicating the acknowledgement.
A method according to claim 17 wherein sending an acknowledge of receipt of the transmission block from the wireless device to the wireless base station comprises using a resource of the at least one Physical Uplink Control Channel overlapped with a resource of at least one Physical Uplink Shared Channel of another wireless device.
A method according to claim 17 or claim 18 wherein detecting receipt of the acknowledgement in the wireless base station comprises monitoring the at least one pre-configured Physical Uplink Control Channel and blind detection of the sequence indicating the acknowledgement.
A method of controlling automatic repetition of data transmission from a wireless base station to a wireless device in a wireless communication network, comprising the steps of:

generating in the wireless base station control information which controls data transmission from the wireless base station to the wireless device,

modifying the control information to include an automatic repetition field having at least one value defining a number of data transmission repetitions, and

transmitting the modified control information from the wireless base station to the wireless device and transmitting data from the wireless base station to the wireless device in accordance with the modified control information.
A method according to claim 20 wherein the automatic repetition field comprises at least one repetition flag bit having a value of one of : a first value equal to 1 which deactivates data transmission repetition; a second value greater than 1 which activates data transmission repetition and indicates the number of data transmission repetitions.
A method according to claim 20 wherein the automatic repetition field comprises a repetition parameter having a value of one of : a first value equal to 1 which deactivates data transmission repetition; a second value greater than 1 which activates data transmission repetition and indicates the number of data transmission repetitions.
A method according to claim 22 wherein the repetition parameter is an aggregationFactorDL repetition parameter.
A method according to claim 20 wherein the method further comprises configuring the automatic repetition field to have two or more values each defining the number of data transmission repetitions and modifying a repetition parameter of an upper layer message of the wireless base station to select one of the values of the automatic repetition field.
A method according to claim 24 wherein the selected value of the automatic repetition field has a value of one of: a first value equal to 1 which deactivates data transmission repetition; a second value greater than 1 which activates data transmission repetition and indicates the number of data transmission repetitions.
A method according to any one of the preceding claims wherein the control information generated by the base station is in the form of Downlink Control Information.
A method according to any one of the preceding claims wherein the modified control information is transmitted from the wireless base station to the wireless device on a Physical Downlink Control Channel.
A method according to any one of the preceding claims wherein the data is transmitted from the wireless base station to the wireless device on at least one Physical Downlink Shared Channel.
A method according to any one of the preceding claims wherein the wireless communication network is a New Radio network supporting Ultra-Reliable and Low-Latency Communications, the wireless base station is a Next Generation Node B base station and the wireless device is a User Equipment.
A wireless base station configured to perform the method of any one of claims 1 to 29.
A wireless device configured to perform the method of any one of claims 1 to 29.