Technical Field

[0001] The present disclosure relates to the field of telecommunications and in particular to a method and device for resource allocation for data transmission between a base station (BS) and a user equipment (UE) in NTN systems. The present disclosure further relates to repetition transmission in the time domain.

[0002] The present disclosure is for example applicable to a telecommunication system such as a 5G (fifth generation) network using the 5G NR (New Radio) as radio access technology (RAT) defined by 3GPP. The present disclosure is applicable to 5G NR (NR in licensed spectrum) but also to 5G NR (NR-U in unlicensed spectrum). The present disclosure is further applicable to Non-terrestrial networks (NTN) systems referring to networks, or segments of networks, using an airborne or spaceborne vehicle for transmission.

Background

[0003] Non-Terrestrial Networks (NTN) (including satellite segments) might form an integral part of 5G connectivity infrastructure. The communication via satellite is an interesting means thanks to its well-known coverage. Satellites refer to spaceborne vehicles in Low Earth Orbits (LEO), Medium Earth Orbits (MEO), Geostationary Earth Orbit (GEO) or in Highly Elliptical Orbits (HEO). Beyond satellites, Non-terrestrial networks (NTN) refer to networks, or segments of networks, using an airborne or spaceborne vehicle for transmission. Airborne vehicles refer to High Altitude Platforms (HAPs) encompassing Unmanned Aircraft Systems (UAS) including tethered UAS, Lighter than Air UAS (LTA) and Heavier than Air (HTA), all operating at altitude; typically between 8 and 50 km, quasi-stationary.

[0004] Nowadays, the satellite communications is a separate technology to 3GPP cellular technology. Coming to 5G era, these two technologies can merge together, i.e. we can imagine to have a 5G terminal that can access to the cellular and satellite network. NTN can be good candidate technology for this purpose. It is to be designed based on 3GPP NR with necessary enhancement.

[0005] In NTN, the network may need to enhance the reliability for certain services. In

NR, this goal may be achieved by deploying slot aggregation, that is, a transmission where the same transport block (TB) is repeated across up to eight slots. The slot aggregation can be configured by the network for PDSCH or PUSCH transmission and is configured in Radio Resource Control (RRC). Moreover, the number of repetitions can also be configured, so-called aggregation factor, which has the choices of 2, 4 and 8.

[0006] However, the slot aggregation is found to have the following drawbacks.

[0007] 3GPP specification Release 15 TS 38.214 5.1.2.1 “Resource allocation in time domain” specifies UE procedure for receiving the physical downlink shared channel (PDSCH), and states that “when receiving PDSCH scheduled by PDCCH with CRC scrambled by C-RNTI, MCS-C-RNTI, CS-RNTI, or PDSCH scheduled without corresponding PDCCH transmission using sps-Config, if the UE is configured with pdsch-AggregationFactor, the same symbol allocation is applied across the pdsch-AggregationFactor consecutive slots. The UE may expect that the TB is repeated within each symbol allocation among each of the pdsch- AggregationFactor.” This part of the 3GPP specification suggests that once the aggregation factor is configured, all the PDSCH transmission will follow this number.

[0008] This may results in that the existing slot aggregation be lack of flexibility, as the slot aggregation cannot be applied to only part of the PDSCH transmission.

[0009] Fig. 1 shows an example of traditional PDSCH repetition (slot aggregation) in cross-slot fashion.

[0010] In this example, PDSCH repetition is realized by inter-slot, that is, the same transport block (in this example PDSCH) is repeated (in each slot the PDSCH time resource are the same) 4 times across 4 different and consecutive slots (maximum up to eight slots).

[0011] In the tradition way of PDSCH repetition, the transmission is slot-based. As shown in Fig. 1, PDSCH transmission awaits for slot boundary for transmission repetition, and the time delay of slot aggregation transmission is calculated by multiplying the slot duration with the repetition number of PDSCH repetition (in this example, 4).

[0012] In NR, the radio frame has a duration of 10ms and consists of 10 sub-frames with a sub-frame duration of 1ms. A sub-frame is formed by one or multiple adjacent slots, each having 14 adjacent symbols.

[0013] Therefore, although the minimum length of a PDSCH time resource is 2 symbols, the slot aggregation service may require much more time resources than needed for repeated transmission.

[0014] The fact that the 3GPP Release. 15 slot aggregation mandates the PDSCH repetitions are transmitted cross different but consecutive slots (as shown in FIG. 1) may result in not only a lack of flexibility in the current system, but also an increase in the time delay given what has been explained above. This is not favorable for time sensitive services. The lack of control of latency becomes less optimal for the case where a mixture of a variety of service types system is provided. [0015] There appears thus a need to solve the problem of lack of flexibility and lack of control of latency.

Summary

[0016] The scope of protection sought for various embodiments of the present disclosure is set out by the independent claims. The various embodiments / examples, aspects and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the present disclosure.

[0017] According to a first aspect of the present disclosure, there is provided a method for communication. The method comprises: receiving, a first indication information and a second indication information, wherein a transmission repetition information for transmission repetition is determined based on the first indication information and the second indication information.

[0018] In some embodiments, the first indication information comprises Radio

Resource Control (RRC) configuration parameters or system information.

[0019] In some embodiments, the second indication information comprises Downlink

Control Information (DCI).

[0020] In some embodiments, the first indication information comprises one value or more than one values of a first parameter.

[0021] In some embodiments, the second indication information is used to indicate to perform or not to perform a transmission repetition configured with the first parameter.

[0022] In some embodiments, the second indication information comprises a first information field, said first information field is used to indicate enabling or disabling a transmission repetition configured with the first parameter.

[0023] In some embodiments, the size of the first information field is one bit.

[0024] In some embodiments, the value of the first information field is 0 or 1.

[0025] In some embodiments, the first parameter has one value.

[0026] In some embodiments, the first parameter has at least two values.

[0027] In some embodiments, the first parameter has at least two values; the second indication information is used to indicate a first target value, of the at least two values of the first parameter.

[0028] In some embodiments, the second indication information comprises a second information field, said second information field is used to indicate the value of the first parameter.

[0029] In some embodiments, the first indication information comprises at least two rows, each row of said at least two rows comprises a row index and a value of said first parameter.

[0030] In some embodiments, the second information field comprises a target row index, said target row index corresponds to the first target value.

[0031] In some embodiments, each row further comprise the value of a third parameter.

[0032] In some embodiments, the first indication information further comprises at least two values of the third parameter, at least two values of the third parameter correspond to at least two values of the first parameter; the second indication information is used to indicate a second target value, of the third parameter, the second target value corresponds to the first target value.

[0033] In some embodiments, the size of the second information field is one bit or two bits.

[0034] In some embodiments, the number of bits of the second information field is the smallest integer number equal to or larger than log2(/) bits, wherein I is the number of values of the first parameter.

[0035] In some embodiments, the first indication information comprises one or at least two values of the first parameter, and one or at least two values of a second parameter.

[0036] In some embodiments, the first parameter has at least two values, the second parameter has at least two values; the second indication information is used to indicate the first target value of the at least two values of the first parameter, and a third target value of the at least two values of the second parameter.

[0037] In some embodiments, the second indication information comprises a third information field, said third information field is used to indicate the first target value and the third target value.

[0038] In some embodiments, the first indication information comprises at least two rows, each row of said at least two rows comprises a value of a fist parameter and/or a value of the second parameter.

[0039] In some embodiments, the third information field comprises target row index, said target row index corresponds to the first target value and/or the third target value.

[0040] In some embodiments, the size (N) of the third information field is the smallest integer equal to or larger than Nl, where iVl = log2(/) bits , wherein I is the number of values of the first parameter, and is the smallest integer equal to or larger than N2 where N 2 — log2 (/) bits , wherein J is the number of values of the second parameter.

[0041] In some embodiments, each row of said at least two rows further comprises a value of the third parameter.

[0042] In some embodiments, the size (N) of the third information field is the smallest integer equal to or larger than N3, where N 3 = log2(/c) bits, wherein k is the number of values of the third parameter.

[0043] In some embodiments, the first indication information further comprises at least two values of the third parameter, the at least two values of the values of the third parameter correspond to at least two values of the first parameter, and correspond to at least two values of the second parameter; the second indication information is used to indicate the second target value of the third parameter, and the second target value corresponds to the first target value and the third target value.

[0044] In some embodiments, the first indication information comprises a first table and a second table, said first table comprises at least two rows, each row of the at least two rows comprises a value of the first parameter and the second list comprises at least two rows, each row comprises a value of the second parameter, the second indication information is used to indicate the target value of the first parameter and the target value of the second parameter. [0045] In some embodiments, the second indication information comprises a fourth information field, and a fifth information field, the fourth information field is used to indicate the target value of the first parameter and the fifth information field is used to indicate the target value of the second parameter.

[0046] In some embodiments, the first table further comprises a third parameter.

[0047] In some embodiments, a value of the third parameter corresponds to a value of the first parameter; the fourth information field is used to indicate the target value of the third parameter.

[0048] In some embodiments, the second table further comprises a fourth parameter.

[0049] In some embodiments, a value of the fourth parameter corresponds to a value of the second parameter; the fifth information field is used to indicate the target value of the fourth parameter

[0050] In some embodiments, the second indication information comprises a first DCI, the first DCI comprises the fourth information field and the fifth information field.

[0051] In some embodiments, the second indication information comprises a first DCI and a second DCI, the first DCI comprises the fourth information field and the second DCI comprises the fifth information field. [0052] In some embodiments, the first parameter comprises repetition number; repetition mode; redundancy version.

[0053] In some embodiments, the second parameter comprises repetition number; repetition mode; redundancy version.

[0054] In some embodiments, the third parameter comprises HARQ process number; start and length indicator value; modulation and coding scheme; PDSCH-to-HARQ feedback timing.

[0055] In some embodiments, the fourth parameter comprises HARQ process number; start and length indicator value; modulation and coding scheme; PDSCH-to-HARQ feedback timing.

[0056] In some embodiments, the DCI is used to schedule uplink transmission or downlink transmission

[0057] In some embodiments, repetition mode comprises a first mode and a second mode; the first mode comprises transmission of PDSCHs being repeated across consecutive slots; the second mode transmission of contiguous PDSCHs being repeated in a slot.

[0058] According to a second aspect of the present disclosure, there is provided a method for communication. The method comprises: receiving, a first indication information, wherein a transmission repetition information for transmission repetition is determined based on the first indication information.

[0059] In some embodiments, the first indication information comprises system block information.

[0060] In some embodiments, transmission repetition is performed in one of the two modes: a first mode comprising transmission of PDSCHs being repeated across consecutive slots; the second mode transmission of contiguous PDSCHs being repeated in a slot.

[0061] In some embodiments, the first indication information comprises at least one of the first parameter and second parameter.

[0062] In some embodiments, the first parameter has one value or at least two values, the second parameter has one value or at least two values.

[0063] In some embodiments, the method comprises using a fallback DCI format to indicate a target value of the first parameter or the second parameter.

[0064] According to a third aspect of the present disclosure, there is provided a device comprising means for performing a method according to the first aspect of the present disclosure or the second aspect of the present disclosure. [0065] According to a fourth aspect of the present disclosure, there is provided a user equipment comprising a device according to the fourth aspect of the present disclosure.

[0066] According to a fifth aspect of the present disclosure, there is provided a method for communication. The method comprises: sending, by a base station, to one or more user equipments (UE) a first indication information and a second indication information.

[0067] According to a sixth aspect of the present disclosure, there is provided a device comprising means for performing a method according to the fifth aspect of the present disclosure.

[0068] According to a seventh aspect of the present disclosure, there is provided a computer readable medium comprising program instructions stored thereon for causing a device to perform the steps of the method according to the first, second or fifth aspect of the disclosure.

Brief Description of the Figures

[0069] Some embodiments are now described, by way of example only, and with reference to the accompanying drawings, in which :

- FIG. 1 shows an example of traditional PDSCH repetition (slot aggregation);

- FIG. 2 shows an example of PDSCH repetition according to some embodiments of the present disclosure;

- FIG. 3 represents schematically a communication system in which one or more disclosed embodiments may be implemented;

- FIG. 4A and 4B are flowcharts of two example respectively implementing method for communication according to the present disclosure performed by a UE;

- FIG. 5 is a flowchart of an example implementation of the method for communication according to the present disclosure performed by a base station;

- FIGs. 6A and 6B illustrate a detailed implementation of the method according to the present disclosure where 1 bit is used for indicating the enabling and the disabling of the repetition respectively; and

- FIG. 7A to 7B show two examples of the method according to the present disclosure based on time domain resource allocation (TDRA) table(s).

Description of Embodiments

[0070] Example embodiments will be described below with reference to functions, engines, block diagrams, flow diagrams, state transition diagrams and / or flowcharts illustrating methods, apparatuses, systems, computer programs, computer readable mediums according to one or more exemplary embodiments.

[0071] FIG. 2 shows an example of PDSCH repetition mode according to the present disclosure.

[0072] As shown in FIG. 2, different from the traditional inter-slot fashion, the PDSCHs are contiguous (back-to-back fashion) and may be repeated in a slot. This mode allows to save allocation resources.

[0073] According to some examples, the transmission repetition may be performed either in the first mode (traditional mode) or in the second mode (proposed by the present disclosure according to FIG. 2), in other words, two possibilities regarding the transmission mode are provided, which can further improve the flexibility.

[0074] In some cases, the two repetition modes may be represented by “0” and “1” but not limited to this expression.

[0075] In some cases, these two repetition modes can be configurable by RRC or system information or DCI or predefined in the specification.

[0076] As the traditional slot aggregation refers only to transmission repetitions across consecutive and different slots (inter-slot fashion), the phrase “transmission repetition” as used in the context of the present disclosure should not be understood in the narrow sense of “slot aggregation” but instead, should comprise other situations, for example where transport blocks are repeated in a back-to-back fashion. Other transmission repetition modes may also be included in “transmission repetition” within the scope of the present disclosure.

[0077] It is to be further noted that although PDSCH repetition configuration are used in most of the examples, similar design can also be applied for other channels, such as PDCCH, PUSCH and PUCCH.

[0078] Although not illustrated in the present disclosure, for PUSCH repetition configuration after RRC configuration, the repetition configuration parameters can be configured under PUSCH-config IE and/or PUSCH-configcommon IE. For PUCCH repetition the RRC configuration parameters can be configured under PUCCH-config IE and/or PUCCH- configcommon IE. For PDCCH repetition, the RRC configuration parameters can be configured under PDCCH-config IE and/or PDCCH-configcommon.

[0079] FIG. 3 depicts an example of non-terrestrial network (NTN) 300, in accordance with some example embodiments. The non-terrestrial network 100 includes a base station 310 in a satellite and one or more user equipment (UE) 320 with the radio cell coverage of the base station. [0080] In the NTN system as shown in FIG. 3, the RTT (round-trip time) latency may be obvious due to the very long distances that the signals must travel into space (i.e. extremely high altitude of satellite) and back. As the connection in NTN system may thus be relatively slow, the gNB 310 may transmit transmission repetition indication information (such as slot aggregation factor, i.e. repetition number, repetition mode, and RRC configuration etc.) by downlink assignment directly to a UE 320 to indicate the UE to perform transmission repetition. In this case, the transmission repetition may refer to PDSCH repetition.

[0081] Alternatively, the transmission repetition may refer to PUSCH repetition where the UE indicates transmission repetition indication information to a gNB via uplink grants. [0082] The examples illustrated here are not limited to NTN system but applicable to other non-NTN communication networks.

[0083] In the following, we will describe several examples that illustrate how the UE may determine transmission repetition information based on received indication information. [0084] FIG. 4A is a flowchart of an example implementation of a method for communication according to the present disclosure performed by a UE.

[0085] As shown in FIG. 4A, in step 401, the UE receives a first indication information and a second indication information. Then in step 402, the UE determines a transmission repetition information for transmission repetition based on the received first indication information and second indication information.

[0086] According to some examples, the first indication information may comprise

RRC configuration parameters or system information.

[0087] In some examples, the first indication information may comprise one or more values of a first parameter, or of a second parameter, or of a third parameter, or of a fourth parameter.

[0088] Repetition parameter may refer to any parameter of the first, the second, the third or the fourth parameter. For example, the repetition parameter may be the repetition number. [0089] In some cases, a repetition parameter may also refer to the value(s) of such a parameter for the convenience of reference, rather than for limiting the scope of the present disclosure.

[0090] In some examples, the first or the second parameter may be a repetition parameter which is configured in RRC configuration such as the repetition number (aggregation factor) and repetition mode. Further, the first or the second parameter may be a resource allocation parameter such as redundancy version (RV).

[0091] In some examples, the third or the fourth parameter may relate to RRC- configured table such as a TDRA table. Such a TDRA table may exist already in the prior art. For example, the third or the fourth parameter may be a start and length indicator value (SLIV) in the RRC -configured table.

[0092] Further, the third or the fourth parameter may be a HARQ process number, modulation and coding scheme or PDSCH-to-HARQ feedback timing (HARQ disabling function). Further, the third or the fourth parameter may be a parameter used for frequency domain resource assignment. Further, the third or the fourth parameter may be a parameter used for time domain resource assignment parameter. The above list should not be considered as exhaustive as other possibilities or different expressions of the above parameters may exist as long as they fall in the context of the present disclosure.

[0093] According to some examples, the first, second, third or fourth parameter may have one value or at least two (more than one) values.

[0094] In some examples, the one value may refer to the single repetition number or a value of the repetition mode, or a value of any of the first, second, third or fourth parameter. [0095] In some examples, where the first parameter is the repetition mode, it has two values which correspond to two repetition modes, respectively.

[0096] In some examples, the at least two values may refer to a set of values, such as a set of repetition numbers {0, 2, 4, 8}. Here there are 4 values of the repetition number.

[0097] In some examples, the at least two values may refer to a list of values of the first, second, third or fourth parameter in at least two rows of a table. The at least two values of the first, second, third or fourth parameter may be in a same table or in different tables.

[0098] In some examples, the first indication information may comprise at least two rows with each row comprising a row index as well as at least one value of the first, second, third or fourth parameter. In some examples, each row may comprise a row index and a combination of value(s) of respective parameters of the first, second, third and/or fourth parameter.

[0099] It is to be noted that when a parameter such as row index, a target row index or a value of the first, second, third or fourth parameter “corresponds to” other parameter(s) such as value(s) of the first, second, third or fourth parameter, this means said parameters are in the same respective row(s).

[00100] It is also to be noted the various combinations of values in a same row as listed in the examples and/or claims are not exhaustive and other combinations although not being presented here may be also possible as long as they fall within the scope of the present disclosure. [00101] According to some examples, the second indication information may be in Downlink Control Information (DCI).

[00102] The DCI is used to provide a device with the necessary information for proper reception and decoding of the downlink data transmission and transmitted in Physical Downlink Control Chanel (PDCCH). Once detecting such a DCI, the device demodulates and decodes the corresponding PDSCH to extract the information carried within the DCI.

[00103] In some examples, the second indication information may be used to indicate to perform or not to perform a transmission repetition being configured with a parameter of the first indication information.

[00104] In an example, one bit of DCI is used to indicate the enabling or disabling of the one value of the transmission repetition.

[00105] In some examples, where the first indication information comprises more than one values of a parameter of the first indication information, the second indication information comprises more than one bits in DCI that are used to indicate the target value of the parameter of the first indication information.

[00106] In some examples, the second indication information may comprise a first information field, a second information field, a third information field, a fourth information field or a fifth information field.

[00107] In the example the size of the first information field is one bit.

[00108] In the example the size of the second information field is one bit or two bits.

[00109] In some examples, an information field in the DCI may be used as an index into a table, such as a TDRA table which is RRC-configured.

[00110] In some examples, the number of bits of the second information field is calculated by taking the smallest integer number equal to or larger than log2(/) bits, wherein I is the number of values of a parameter of the first indication information.

[00111] For example, where the first indication information comprises one or more values of a first parameter, the number of bits of the information field in the second indication information is the smallest integer number equal to or larger than log2(/) bits, wherein I is the number of values of the first parameter.

[00112] For example, where the first indication information comprises values of the first parameter and of the second parameter, the number of bits of the information field, in the second indication information for the target value of the first parameter and second parameter, respectively, is the smallest integers respectively equal to or larger than N 1 and N2, wherein iVl = log2(/) bits , wherein I is the number of values of the first parameter, and N 2 — log2 (/) bits , wherein J is the number of values of the second parameter.

[00113] For example, where the first indication information comprises values of the first parameter, of the second parameter and/or of the third parameter, the number of bits of the information field, in the second indication information for the target value of the first parameter and the second parameter and/or the third parameter, respectively, is the smallest integers respectively equal to or larger than Nl, N2 and N3, wherein iVl = log2(/) bits , wherein I is the number of values of the first parameter, and N 2 — log2 (/) bits , wherein J is the number of values of the second parameter, and N 2 — log2 (K) bits , wherein K is the number of values of the third parameter.

[00114] Further, in some examples, where the first indication information comprises repetition parameters and further comprises HARQ ID numbers. In other words, in the first indication information, there may be multiple sets of HARQ process for example two sets each configured with respective repetition parameters. The second indication information is in DCI which comprises a given HARQ ID that belongs to a specific set of HARQ IDs. In this example the second indication information comprises HARQ process number. When the first indication information and the second indication information are received, the repetition configuration can be determined based on a given HARQ process ID in the DCI scheduling information.

[00115] Still further in some other examples, where the first indication information comprises a first parameter and further comprises a third parameter such as specific HARQ ID numbers. In other words, the RRC configuration further comprises HARQ disabling information which comprises at least one HARQ process IDs (as the values of the third parameter), the ACK/NACK of the HARQ process of which are disable (if the PDSCh is scheduled with these HARQ process ID, the UE does not feedback the ACK/NACK). The second indication information is in DCI which indicates a HARQ ID. In this example the second indication information comprises HARQ process number. If the HARQ ID indicated by the DCI is included in the HARQ disabling information of the first indication information, then transmission repetition will be performed as configured by the first parameter.

[00116] In some examples, DCI separately indicates a transmission repetition parameter such as a repetition number.

[00117] For example, where the first indication information comprises one value of repetition number, one bit in DCI may be introduced to indicate whether to perform transmission repetition which is configured with the repetition number by RRC configuration. [00118] For example, where the first indication information comprises at least two values of repetition number {0, 2, 4, 8}, two bits in DCI may be introduced to indicate a target value, that is, which value is selected as the repetition number to perform transmission repetition. [00119] Separately indicating may use separate bit(s) in DCI to indicate the repetition information. It has the advantage of being highly flexible as it does not need to be combined with any existing configurations. However, the drawback is that more bits are required for the indication. So it may be sued when flexibility is more important than a small overhead.

[00120] In some examples, DCI jointly indicates a transmission repetition parameter. [00121] For example, where the first indication information comprises a RRC -configured TDRA table comprising at least two rows each of which comprising a row index with at least a value of a parameter of the first, second, third, or fourth parameter, a repetition parameter may be jointly configured with the TDRA table, and in DCI the indicated index gives the transmission repetition information such as SLIV value and repetition parameters.

[00122] Different from the separately indicating, the jointly indicating will not generate extra overhead but it may be less flexible than a separate indication.

[00123] FIG. 4B shows another example implementation of a method for communication according to the present disclosure performed by a UE.

[00124] As shown in FIG. 4B, in step 401, the UE receives a first indication information. Then in step 402, the UE determines a transmission repetition information for transmission repetition based on the received first indication information.

[00125] Different from FIG. 4A, FIG. 4B shows the method where the transmission repetition is configured before RRC configuration, such as during the initial access phase. [00126] In some examples, instead of being RRC-configured, the first indication information is directly configured in the system block information (SIB), such as PDSCH- configcommon IE.

[00127] For example, the first indication information comprises at least one of the first parameter and the second parameter.

[00128] In an example, the first and second parameters each has one value. The first parameter is repetition number and the second parameter is repetition mode. In an example, the repetition number is 4, and the repetition mode is “0”.

[00129] In another example, the first parameter is the repetition number and has at least two values. For example, a set of repetition numbers {0, 2, 4, 8} is configured. In this example, the fallback DCI (DCI format 1_0) is used to indicate which repetition number from the set is selected for each PDSCH scheduling.

[00130] In some examples, the fallback DCI (DCI format 1_0) has a fixed size. Therefore, the number of the values of a repetition parameter is limited by the size of the DCI (indication field). Assuming the size of the DCI indication field is N bits, then the number I of values of a repetition parameter such as values of the repetition number is calculated by I = 2 ^N . Advantageously, the values of the repetition parameter can be configured in system information, e.g. SIB 1, then fallback DCI (DCI format 1_0) can indicate the target value of the configured repetition parameter.

[00131] Alternatively, the repetition is jointly indicated with a TDRA table. However, this table is a default table in the initial access phase and the elements of which cannot be configured by the SIB signaling. In this example, the DCI can only use index to select which table is to be used. Advantageously, to enhance the flexibility, there can be more than one default TDRA tables, each jointly defined with different values of the repetition parameter. The SIB signaling can select target TDRA table.

[00132] FIG. 5 is a flowchart of an example implementation of the method for communication according to the present disclosure performed by a base station.

[00133] As shown in FIG. 5, in step 501, a base station sends to one or more UEs a first indication information and a second indication information.

[00134] In a NTN system, the base station may sends the first indication information and the second indication information via downlink transmission to a UE directly, and the UE will determine a transmission repetition information for transmission repetition based on received information.

[00135] The system may be other systems than a NTN system which experience less obvious latency than the NTN system.

[00136] Further examples will now be described by reference to FIGS. 6, 7 A and 7B.

[00137] Example 1: DCI indicating enabling/disabling of a repetition parameter [00138] FIGs. 6A and 6B illustrate a detailed implementation of the method according to the present disclosure where 1 bit is used for indicating the enabling and the disabling of the repetition respectively.

[00139] Existing RRC configuration has provided an approach to enable or to disable the repetition. For example, to configure that the repetition is enabled, it can be configured in PDSCH_config IE with the number of repetition (K_rep) being 2, 4, 8 or other integer numbers greater than 1. To configure that the repetition is disabled, it can also be configured in PDSCH_config IE but without configuring the repetition parameter, so that a UE will understand that the repetition is disabled. The enabling/disabling provides a switch function to the repetition parameter. [00140] However, the above solution of configuring or not configuring the repetition parameter with RRC in order to provide the switch function seems to be a simple but lack of flexibility.

[00141] In order to improve the flexibility, we can use RRC and DCI to jointly indicate PDSCH repetition.

[00142] Similar to the above solution, the repetition parameter is configured in RRC configuration, but once it is configured, switching between enabling/disabling of the repetition parameter will depend on the DCI indication.

[00143] In the examples according to FIGs. 6 A and 6B, In DCI, a first information field is introduced, such as a repetition field (Rep), which can be 1-bit enabling/disabling indication to tell UE if the scheduled PDSCH should be applied with repetition.

[00144] As shown in FIG. 6A, if the Rep bit is ‘G, the PDSCH will be applied with configured repetition parameter(s) where the PDSCH is repeated 4 times in a first repetition mode (traditional inter-slot fashion).

[00145] As shown in FIG. 6B, if the Rep bit is O’, the PDSCH will not be applied with the configured repetition parameter(s). In other words, the transmission repetition configured with the repetition parameter(s) is not performed.

It is to be noted that the choice of Rep bit value may be different, for example, “1” may indicate the PDSCH repetition parameter(s) not be applied and vice versa.

[00146] Example 2: repetition parameter (repetition number) jointly configured with a TDRA table

[00147] FIG. 7A shows an example of the method according to the present disclosure where the repetition number is jointly configured with a TDRA table.

[00148] Instead of having a fixed number in RRC configuration, the DCI can dynamically indicate the repetition number.

[00149] According to FIG. 7A, this is achieved by using a RRC-configured TDRA table which exists already in the prior art.

[00150] In some examples, the TDRA table contains SLIV parameter, which is used to determine the time resource allocation. In this example, the TDRA table comprises at least two rows, such as 16 rows; each row comprises an index number and a SLIV value.

[00151] Based on the TDRA table, we can add one more column ‘rep number’ to the table to configure different repetition number. In this example, 16 rows of repetition numbers are provided. [00152] The DCI will indicate the index row, then the UE will determine the first PDSCH time domain resource by SLIV value and the UE will determine the repetition number by the last column. If the repetition number is 0, it means the no repetition is performed. If the repetition number is a non-zero integer, for example the row index =1 is selected where the repetition number is 2, then the PDSCH corresponding to the SLIV value in that row will be repeated 2 times.

[00153] This approach can further improve the flexibility for the repetition.

[00154] Example 3: repetition parameters (repetition number and repetition model jointly configured with a TDRA table

[00155] Not only the repetition number, other repetition parameter such as repetition mode may also be jointly configured with a TDRA table. In other words, DCI can dynamically indicate both the repetition number and the repetition mode.

[00156] As shown in FIGs. 1-2, PDSCH repetition mode can be cross-slot or back-to- back.

[00157] Similar to the RRC-configuration for enabling/disabling function, these two different repetition modes can also be simply configured by RRC by introducing repetition mode parameter, e.g. ‘rep_mod’. However, the solution is lack of the flexibility.

[00158] As shown in FIG. 7B, the repetition mode can also be configured jointly with TDRA table based on the configuration according FIG. 7A, where the last column represents the repetition mode with O’ being cross-slot mode and ‘1’ being the back-to-back mode. [00159] Similar to the explanations to FIG. 7A, in DCI the indicated index will give the SLIV value, the repetition number and repetition mode.

[00160] Although not shown in the figures, the repetition configuration may also be associated with HARQ-related information.

[00161] In some examples, the repetition configuration can be associated with HARQ process ID.

[00162] For example, the network can configure repetition number and repetition mode for a set of HARQ process IDs. If the network configures multiple sets of HARQ process, different repetition configurations can be realized.

[00163] For example, the network can configure two sets: Set 1 { HARQ ID0-HARQ ID7} and Set 2 {HARQ ID8-HARQ ID 15}. For HARQ process Set 1, the repetition configuration can be repetition number=4 and repetition mode=0. While for HARQ process Set 2, the repetition configuration can be repetition number=0. [00164] Thus, a UE can immediately determine the repetition configuration once it obtains a PDSCH scheduling with a given HARQ process ID.

[00165] In some other examples, the repetition configuration is associated with HARQ disabling function.

[00166] Given an example in the NTN system, the HARQ disabling refers to the UE is requested not to feedback the Ack/Nack of the received PDSCH for a given HARQ process. More specically, if the PDSCH is scheduled with these HARQ process ID, the UE does not feedback the Ack/Nack.

[00167] This function can also be associated with the repetition configuration. In an example, the repetition is configured only for HARQ disabled process.

[00168] For example, the network configures 16 HARQ processes with HARQ IDO- 15. The network can configure HARQ ID0-3 as HARQ disabled process, and the rest of the HARQ processes are HARQ enabled process.

[00169] Further, the network configures repetition configuration, e.g. repetition number = 2, repetition mode=0.

[00170] Then the association is that once the PDSCH is scheduled with the HARQ disabled process (i.e. HARQ ID0-3), the PDSCH will be applied with the corresponding repetition parameters. Otherwise, if the PDSCH is scheduled with other HARQ process ID, repetition is not applied.

[00171] The advantage of this design is that the repetition is used when the PDSCH transmission reliability is low. HARQ disabling will normally lower down the transmission reliability while by applying the repetition, the reliability can be enhanced.

[00172] All the examples illustrated above are likewise applicable to other types of transmissions whether in the time domain or in the frequency domain, whether they are downlink or uplink transmissions.

[00173] It should be appreciated by the man skilled in the art that any functions, engines, block diagrams, flow diagrams, state transition diagrams and / or flowcharts herein represent conceptual views of illustrative circuitry embodying the principles of the invention. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processing apparatus, whether or not such computer or processor is explicitly shown.

[00174] Each described function, engine, block, step may be implemented in hardware, software, firmware, middleware, microcode, or any suitable combination thereof. If implemented in software, the functions, engines, blocks of the block diagrams and/or flowchart illustrations may be implemented by computer program instructions / software code, which may be stored or transmitted over a computer-readable medium, or loaded onto a general purpose computer, special purpose computer or other programmable processing apparatus and / or system to produce a machine, such that the computer program instructions or software code which execute on the computer or other programmable processing apparatus, create the means for implementing the functions described herein.

[00175] Implementations of the various techniques and methods described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Implementations may implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device or in a propagated signal, for execution by, or to control the operation of, a data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. Implementations may also be provided on a computer readable medium or computer readable storage medium, which may be a non-transitory medium.

[00176] In the present document, the wording "means configured to perform ....” a function shall be understood as functional block(s) comprising circuitry that is adapted for performing or configured to perform the function. Moreover, any entity described herein as "means", may correspond to or be implemented as "one or more modules", "one or more devices", "one or more units", etc. Means for performing one or more functions may for example comprises at least processor and at least one memory (e.g. in a system or apparatus) for storing computer program code configured to, with the at least one processor, cause the performance (by a system or corresponding device) of the one or more functions.

[00177] When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. The functions of the various elements shown in the figures, including any functional blocks labeled as “processors”, may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software.

[00178] Moreover, explicit use of the term "processor" or "controller" should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, network processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), read only memory (ROM) for storing software, random access memory (RAM), and non-volatile storage. Other hardware, conventional or custom, may also be included. Their function may be carried out through the operation of program logic, through dedicated logic, through the interaction of program control and dedicated logic, or even manually, the particular technique being selectable by the implementer as more specifically understood from the context.

[00179] The term “circuitry” may refer to hardware-only circuit implementations; combinations of circuits and software and/or firmware; or hardware circuit(s) and/or processor(s), such as a microprocessors or a portion of a microprocessor(s), that require or not software and / or firmware for operation, whether the software or firmware is or not physically present. A circuitry may be a general purpose circuitry or a special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application- specific integrated circuit). The term circuitry also covers, for example and if applicable to the particular claimed element, a baseband integrated circuit, processor integrated circuit or a similar integrated circuit for a base station and / or user equipment.

[00180] Some embodiments are also intended to cover computer-readable medium, e.g., digital data storage media, which are machine or computer readable and encode machine- executable or computer-executable programs of instructions, wherein such instructions are configured to cause the execution of some or all of the steps of said above-described methods by a corresponding apparatus, device or system. The computer-readable medium may be, e.g., digital memories, magnetic storage media such as a magnetic disks and magnetic tapes, hard drives, or optically readable digital data storage media.

[00181] Embodiments of a computer-readable medium includes, but are not limited to, both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. Specifically, program instructions or computer readable program code to perform embodiments described herein may be stored, temporarily or permanently, in whole or in part, on a non-transitory computer readable medium of a local or remote storage device including one or more storage media.

[00182] The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, distribution medium, or computer readable medium, which may be any entity or device capable of carrying the program. Such carriers include a record medium, computer memory, read-only memory, photoelectrical and/or electrical carrier signal, telecommunications signal, and software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital computer or it may be distributed amongst a number of computers. [00183] A computer program, such as the computer program(s) described above, may be written in any form of programming language, including compiled or interpreted languages, and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit or part of it suitable for use in a computing environment. A computer program may be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

[00184] In addition, a computer-readable storage medium may be provided that includes stored instructions, which when executed by the processor 1008 performs one or more of the functions, steps or tasks described above for the concerned device.

[00185] For example, the device 1000 also may include, or be operatively coupled to receive data from or transfer data to, or both, one or more computer-readable storage mediums, e.g., magnetic, magneto -optical disks, or optical disks. A computer-readable storage medium suitable for embodying computer program instructions and data include all forms of non volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks.

[00186] The processor 1008 may be configured to access to one or more memories for storing instructions and data and to execute instructions. The processor 1008 may be configured to store, read, load and/or otherwise process computer program code stored in a computer- readable storage medium and / or in the memory 1006 that, when executed by the at least one processor, causes the device 1000 to perform one or more steps of a method described herein for the concerned device 1000. Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer, chip or chipset. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. [00187] The processor 1008 may be any suitable processor, e.g. a microprocessor, microcontroller, integrated circuit, or central processing unit (CPU) including at least one hardware-based processor or processing core.

[00188] The memory 1006 may include a random access memory (RAM), cache memory, non-volatile memory, backup memory (e.g., programmable or flash memories), read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD) or any combination thereof. The ROM of the memory 1006 may be configured to store, amongst other things, an operating system of the device 1000 and / or one or more computer program codes of one or more computer programs. The RAM of the memory 1006 may be used by the processor 1008 for the temporary storage of data.

[00189] The description and drawings merely illustrate the principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope.

[00190] Furthermore, all examples recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.

[00191] In the above description, the mobile telecommunication system is a 5G mobile network comprising a 5G NR access network. The present example embodiment is applicable to NR in unlicensed spectrum (NR-U) and also to NR in licensed spectrum (NR). The present disclosure can be applied to other mobile networks, in particular to mobile network of any further generation cellular network technology (6G, etc.). [00192] A list of acronyms used in this document is provided below

[00193] A person of skill in the art would readily recognize that one or more or all steps of the various methods described herein can be performed by programmed computers.

[00194] Herein, some embodiments are also intended to cover program storage devices, e.g., digital data storage media, which are machine or computer readable and encode machine- executable or computer-executable programs of instructions, wherein such instructions are configured to cause the execution of some or all of the steps of said above-described methods by a corresponding apparatus or system. The program storage devices may be, e.g., digital memories, magnetic storage media such as a magnetic disks and magnetic tapes, hard drives, or optically readable digital data storage media. The embodiments are also intended to cover computers programmed to perform said steps of the above-described methods.

[00195] Embodiments of a computer-readable medium includes, but are not limited to, both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. Specifically, program instructions or computer readable program code to perform embodiments described herein may be stored, temporarily or permanently, in whole or in part, on a non-transitory computer readable medium of a local or remote storage device including one or more storage media.

[00196] In addition, a storage medium may be provided that includes stored instructions, which when executed by the processor performs one or more of the functions, steps or tasks described above for the concerned device.

[00197] The embodiments are not, however, restricted to the system that is given as an example, but a person skilled in the art may apply the solution to other communication systems. Another example of a suitable communications system is the 5G concept. It is assumed that network architecture in 5G will be quite similar to that of the LTE-advanced. 5G is likely to use multiple input - multiple output (MIMO) antennas, many more base stations or nodes than the LTE (a so-called small cell concept), including macro sites operating in cooperation with smaller stations and perhaps also employing a variety of radio technologies for better coverage and enhanced data rates.

[00198] Implementations of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Implementations may implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device or in a propagated signal, for execution by, or to control the operation of, a data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. Implementations may also be provided on a computer readable medium or computer readable storage medium, which may be a non-transitory medium.

[00199] The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, distribution medium, or computer readable medium, which may be any entity or device capable of carrying the program. Such carriers include a record medium, computer memory, read-only memory, photoelectrical and/or electrical carrier signal, telecommunications signal, and software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital computer or it may be distributed amongst a number of computers.

[00200] Furthermore, implementations of the various techniques described herein may use a cyber-physical system (CPS) (a system of collaborating computational elements controlling physical entities). CPS may enable the implementation and exploitation of massive amounts of interconnected ICT devices (sensors, actuators, processors, microcontrollers,...) embedded in physical objects at different locations.

[00201] A computer program, such as the computer program(s) described above, can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit or part of it suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network. [00202] Method steps may be performed by one or more processors executing a computer program or computer program portions to perform functions by operating on input data and generating output. Method steps also may be performed by, and an apparatus may be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application- specific integrated circuit).

[00203] Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer, chip or chipset. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. Elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer also may include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto -optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non volatile memory, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory may be supplemented by, or incorporated in, special purpose logic circuitry.

[00204] The description and drawings merely illustrate the principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope.

[00205] Furthermore, all examples recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.