Method and apparatus for allocating resource in wireless communication system

Abstract

The present disclosure relates to a 5G communication system or a 6G communication system for supporting higher data rates beyond a 4G communication system such as long term evolution (LTE). The present disclosure relates, in general, to wireless communications and, in particular, to devices and methods for allocating resources in the time domain based on aggregation thereof. A method is provided for allocating resources in the time domain in a wireless communication system.

Description

METHOD AND APPARATUS FOR ALLOCATING RESOURCE IN WIRELESS COMMUNICATION SYSTEM

[0001] The present disclosure relates, in general, to wireless communication system (or mobile communication system). Also, in particular, the present disclosure relates to devices and methods for allocating resources in the time domain based on aggregation thereof.

[0002] Considering the development of wireless communication from generation to generation, the technologies have been developed mainly for services targeting humans, such as voice calls, multimedia services, and data services. Following the commercialization of 5G (5th generation) communication systems, it is expected that the number of connected devices will exponentially grow. Increasingly, these will be connected to communication networks. Examples of connected things may include vehicles, robots, drones, home appliances, displays, smart sensors connected to various infrastructures, construction machines, and factory equipment. Mobile devices are expected to evolve in various form-factors, such as augmented reality glasses, virtual reality headsets, and hologram devices. In order to provide various services by connecting hundreds of billions of devices and things in the 6G (6th generation) era, there have been ongoing efforts to develop improved 6G communication systems. For these reasons, 6G communication systems are referred to as beyond-5G systems.

[0003] 6G communication systems, which are expected to be commercialized around 2030, will have a peak data rate of tera (1,000 giga)-level bit per second (bps) and a radio latency less than 100μsec, and thus will be 50 times as fast as 5G communication systems and have the 1 / 10 radio latency thereof.

[0004] In order to accomplish such a high data rate and an ultra-low latency, it has been considered to implement 6G communication systems in a terahertz (THz) band (for example, 95 gigahertz (GHz) to 3THz bands). It is expected that, due to severer path loss and atmospheric absorption in the terahertz bands than those in mmWave bands introduced in 5G, technologies capable of securing the signal transmission distance (that is, coverage) will become more crucial. It is necessary to develop, as major technologies for securing the coverage, Radio Frequency (RF) elements, antennas, novel waveforms having a better coverage than Orthogonal Frequency Division Multiplexing (OFDM), beamforming and massive Multiple-input Multiple-Output (MIMO), Full Dimensional MIMO (FD-MIMO), array antennas, and multiantenna transmission technologies such as large-scale antennas. In addition, there has been ongoing discussion on new technologies for improving the coverage of terahertz-band signals, such as metamaterial-based lenses and antennas, Orbital Angular Momentum (OAM), and Reconfigurable Intelligent Surface (RIS).

[0005] Moreover, in order to improve the spectral efficiency and the overall network performances, the following technologies have been developed for 6G communication systems: a full-duplex technology for enabling an uplink transmission and a downlink transmission to simultaneously use the same frequency resource at the same time; a network technology for utilizing satellites, High-Altitude Platform Stations (HAPS), and the like in an integrated manner; an improved network structure for supporting mobile base stations and the like and enabling network operation optimization and automation and the like; a dynamic spectrum sharing technology via collision avoidance based on a prediction of spectrum usage; an use of Artificial Intelligence (AI) in wireless communication for improvement of overall network operation by utilizing AI from a designing phase for developing 6G and internalizing end-to-end AI support functions; and a next-generation distributed computing technology for overcoming the limit of UE computing ability through reachable super-high-performance communication and computing resources (such as Mobile Edge Computing (MEC), clouds, and the like) over the network. In addition, through designing new protocols to be used in 6G communication systems, developing mechanisms for implementing a hardware-based security environment and safe use of data, and developing technologies for maintaining privacy, attempts to strengthen the connectivity between devices, optimize the network, promote softwarization of network entities, and increase the openness of wireless communications are continuing.

[0006] It is expected that research and development of 6G communication systems in hyper-connectivity, including person to machine (P2M) as well as machine to machine (M2M), will allow the next hyper-connected experience. Particularly, it is expected that services such as truly immersive eXtended Reality (XR), high-fidelity mobile hologram, and digital replica could be provided through 6G communication systems. In addition, services such as remote surgery for security and reliability enhancement, industrial automation, and emergency response will be provided through the 6G communication system such that the technologies could be applied in various fields such as industry, medical care, automobiles, and home appliances.

[0007] Nowadays more and more active deployment of 5th Generation (5G) New Radio (NR) networks takes place whose advantages and capabilities are broadly known. Also, there are needs to enhance resource allocation in consideration of carrier aggregation.

[0008] An object of the present disclosure relates to providing a technique which is intended for allocating time domain resources for broadband data transmission based on aggregation of the resources and which would allow, on one hand, to avoid the increased DMRS overhead, and, on the other hand, to avoid negative effects that may arise due to using longer TTIs resulting from the aggregation.

[0009] In the context of said object, according to the first aspect of the present disclosure a method of allocating resources in a time domain in a wireless communication system. The method provided herein comprises: in a base station (TRP), allocating a predetermined number of adjacent OFDM-symbols for transmission of a physical downlink control channel (PDCCH); allocating a bundle of time intervals (TTI), the TTI comprising a set of adjacent time intervals (sub-TTIs), wherein each sub-TTI includes a predetermined number of OFDM-symbols, wherein an identifier is assigned to each sub-TTI in the TTI, where the identifier is preferably a HARQ ID; allocating, within the TTI, a subset of adjacent sub-TTIs for transmission of a physical downlink shared channel (PDSCH) to a user device (UE); reserving the TTI for the transmission of the PDSCH to the user device by transmitting to the UE the PDCCH which carries downlink control information (DCI) including at least information enabling to determine identifiers of all the sub-TTIs in the TTI; and transmitting the PDSCH to the UE in said subset of sub-TTIs. As discussed previously, a time interval (sub-TTI) may represent a slot comprising 12 or 14 OFDM-symbols, or a mini-slot comprising 2, 4, or 7 OFDM-symbols. Said information enabling to determine the identifiers of all the sub-TTIs may represent an array of the identifiers of the sub-TTIs of the reserved TTI. The method provided herein further comprises informing the UE about sub-TTIs of the reserved TTI which are not comprised by the subset of sub-TTIs.

[0010] According to an embodiment, the method further comprises, in the user device: placing, into a buffer, received data from all the sub-TTIs of the reserved TTI; and, with respect to each of the sub-TTIs of the reserved TTI, decoding, from the buffer, data corresponding to the sub-TTI, and sending to the base station an acknowledgement in a physical uplink control channel (PUCCH). If the decoding is successful: a positive acknowledgement (ACK) is sent as said acknowledgement, and the corresponding data is removed from the buffer, and if the decoding is unsuccessful: a negative acknowledgement (NACK) is sent as said acknowledgement, and the corresponding data is left in the buffer. It should be emphasized at this point that decoding of data from the sub-TTIs of the reserved TTI which are not comprised by said subset of sub-TTIs is always unsuccessful.

[0011] Moreover, according to this embodiment, the method further comprises: in the base station, upon reception of NACK with respect to data transmitted in a sub-TTI of the subset of sub-TTIs, retransmitting said data to the user device; and, in the user device, combining the retransmitted data received in the user device with data from the buffer that corresponds to said sub-TTI, and decoding the combined data.

[0012] According to the one embodiment, said informing may represent explicit informing which comprises, in the base station: transmitting, within subsequent DCI, identifiers of all the sub-TTIs of said subset of sub-TTIs or identifiers of the sub-TTIs of the TTI which are not comprised by the subset of sub-TTIs. In accordance with this embodiment, the method further comprises, in the user device: upon reception of the subsequent DCI, removing, from the buffer, data corresponding to the sub-TTIs not comprised by the subset of sub-TTIs.

[0013] According to the other embodiment, said informing may represent implicit informing.

[0014] According to another embodiment, the predefined duration of the timer is set in the base station and signaled, prior to the starting, to the user device by MAC signaling or RRC signaling.

[0015] According to another embodiment, wherein a plurality of used identifiers is maintained in the user device for time intervals whose data have been placed into the buffer, wherein the plurality of used identifiers is added with the identifiers of the timer intervals of the bundle of time intervals, and identifiers of time intervals whose corresponding data are removed from the buffer are excluded from the plurality of used identifiers.

[0016] According to another embodiment, wherein the information enabling to determine the identifiers of all the time intervals of the bundle of time intervals represents an array of the identifiers of the time intervals of the bundle of time intervals.

[0017] In accordance with one possible implementation of said other embodiment, the method provided herein further comprises: starting a timer of a predefined duration in the base station after the transmission of the DCI in the PDCCH, and starting a timer of the predefined duration in the user device upon reception of the DCI, with account of time of signal propagation between the base station and the user device. The method also comprises, in the user device, upon expiration of the predefined duration of the timer: determining, as the sub-TTIs not comprised by the subset of sub-TTIs, sub-TTIs with respect to which NACKs were sent from the user device to the base station and for which retransmitted data were not received from the base station within said predefined duration, thereby implementing said implicit informing; and removing, from the buffer, data corresponding to the determined sub-TTIs.

[0018] In accordance with an alternative implementation of said other embodiment, the method further comprises: starting an individual timer of a predefined duration in the base station upon completion of transmission in each sub-TTI of the reserved TTI, and starting a timer of the predefined duration in the user device upon reception of data in said sub-TTI, with account of time of signal propagation between the base station and the user device. The method also comprises, in the user device: upon expiration of the predefined duration of the timer, determining said sub-TTI as a sub-TTI which is not comprised by the subset of sub-TTIs if, for said sub-TTI, NACK was sent from the user device to the base station and retransmitted data was not received from the base station within said predefined duration, thereby implementing said implicit informing; and removing, from the buffer, data corresponding to the determined sub-TTIs.

[0019] The predefined duration of the timer is set in the base station and signaled, prior to the starting, to the user device preferably by MAC signaling or RRC signaling.

[0020] According to an embodiment, a plurality of available identifiers is maintained in the base station which are available for being assigned to sub-TTIs. Upon said reserving, the identifiers assigned to the sub-TTIs of the reserved TTI are excluded from the plurality of available identifiers. The plurality of available identifiers is added with identifiers with respect to which ACKs have been received in the base station from the user device. Finally, upon said informing, the plurality of available identifiers is added with the identifiers of the sub-TTIs which have not been comprised by said subset of sub-TTIs.

[0021] In accordance with this embodiment, a plurality of used identifiers is maintained in the user device for sub-TTIs whose data have been placed into the buffer. Upon said placing data into the buffer, the plurality of used identifiers is added with the identifiers of the sub-TTIs of the reserved TTI. Identifiers of sub-TTIs whose corresponding data are removed from the buffer are excluded from the plurality of used identifiers.

[0022] According to the second aspect of the present disclosure, a base station (TRP) in a wireless communication system is provided, the base station comprising, at least: transceiving units; data processing units; and data storage units having computer-executable codes stored therein which, when executed by the data processing units, cause the base station to perform the method according to the first aspect in the embodiment with the explicit informing.

[0023] According to the third aspect of the present disclosure, a wireless communication system is provided that comprises at least a base station (TRP), the TRP comprising, at least: transceiving units; data processing units; and data storage units, wherein the TRP is configured to communicate with a user device (UE) comprising, at least: transceiving units; data processing units; and data storage units, wherein the data storage units of the TRP have computer-executable codes stored therein, and the data storage units of the UE have computer-executable codes stored therein, wherein the computer-executable codes, when executed by the data processing units of the TRP and the UE, cause the method according to any embodiment of the first aspect of the present disclosure to be performed.

[0024] The technical result achievable by the present disclosure relates to providing the efficient technique of allocating time domain resources based on flexible aggregation of slots or mini-slots, along with providing a larger unit of allocating / scheduling resources in the time domain, thereby enabling, on one hand, to use less frequent transmissions of DMRSs and PDCCH and, in turn, to at least avoid the increased overhead, which is especially urgent in the case of DMRS patterns of greater capacity for next generation communication systems, and, on the other hand, to avoid negative effects caused by usage of such an aggregated unit. More specifically, in the context of avoiding said negative effects, simpler preparation of DCI and less demands on buffering in a base station when scheduling downlink transmission are provided, as well as reduced latency for downlink transmission of new data is provided.

[0025] According to various embodiments of the disclosure, resource allocation in time domain can be efficiently enhanced by considering of carrier aggregation.

[0026] Fig.1 is an illustrative scheme of spatial processing of signals at the transmitter side;

[0027] Figs.2a is an illustration of allocating time resources in 5G NR;

[0028] Figs.2b is an illustration of allocating time resources in 5G NR;

[0029] Figs.2c is an illustration of allocating time resources in 5G NR;

[0030] Fig.3 is an illustrative scheme of a wireless communication system in which embodiments of the present disclosure can be implemented;

[0031] Fig.4 is an illustration of an attempt to use the 5G NR approach to allocating time resource in a next generation wireless communication system;

[0032] Figs.5a is an exemplary embodiment of the general approach to aggregating time domain resources for the DL part of a DL / UL period of a frame according to the present application;

[0033] Figs.5a is an exemplary embodiment of the general approach to aggregating time domain resources for the DL part of a DL / UL period of a frame according to the present application;

[0034] Figs.6a is a high-level representation of the general approach to resource aggregation according to the present application;

[0035] Figs. 6b is a high-level representation of the general approach to resource aggregation according to the present application;

[0036] Fig.7 is an illustration of an embodiment of aggregating time domain resources to provide pipelining of processing of code blocks at the receiver side according to the present application;

[0037] Figs.8a is a flowchart of the method of allocating resources in the time domain according to an embodiment of the general approach to aggregating resources according to the present application;

[0038] Figs. 8b is a flowchart of the method of allocating resources in the time domain according to an embodiment of the general approach to aggregating resources according to the present application;

[0039] Fig.9 is an illustration of drawbacks associated with time resource aggregation in accordance with the general approach according to the present application;

[0040] Figs.10a is an illustration of the concept of flexible allocation of time resources according to the present disclosure;

[0041] Figs. 10b is an illustrations of the concept of flexible allocation of time resources according to the present disclosure;

[0042] Fig.11 is a detailed illustration of an embodiment of flexible allocation of time resources according to the present disclosure with explicit informing of the UE about time resources used for actual transmission of the PDSCH;

[0043] Fig.12 is a general illustrative scheme of exchanging transmissions between the TRP and the UE according to an embodiment of the present disclosure;

[0044] Fig.13 is an illustration of the sequence of operations performed when explicitly informing the UE about time resources used for actual transmission of the PDSCH, according to an embodiment of the present disclosure;

[0045] Fig.14 is an illustration of the sequence of operations performed when implicitly informing the UE about time resources used for actual transmission of the PDSCH, according to an embodiment of the present disclosure;

[0046] Fig.15 is a flowchart of the method of flexibly allocating resources in the time domain according to an embodiment of the present disclosure;

[0047] Fig. 16 is a block diagram showing a structure of a terminal according to an embodiment of the disclosure; and

[0048] Fig. 17 is a block diagram showing a structure of a base station according to an embodiment of the disclosure.

[0049] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

[0050] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.

[0051] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces.

[0052] The term “include” or “may include” refers to the existence of a corresponding disclosed function, operation or component which can be used in various embodiments of the present disclosure and does not limit the existence of one or more additional functions, operations, or components. The terms such as “include” and / or “have” may be construed to denote a certain characteristic, number, step, operation, constituent element, component or a combination thereof, but may not be construed to exclude the possibility of existence of one or more other characteristics, numbers, steps, operations, constituent elements, components or combinations thereof.

[0053] The term “or” used in various embodiments of the present disclosure includes any or all of combinations of listed words. For example, the expression “A or B” may include A, may include B, or may include both A and B.

[0054] Unless defined differently, all terms used herein, which include technical terminologies or scientific terminologies, have the same meaning as that understood by a person skilled in the art to which the present disclosure belongs. Such terms as those defined in a generally used dictionary are to be interpreted to have the meanings equal to the contextual meanings in the relevant field of art, and are not to be interpreted to have ideal or excessively formal meanings unless clearly defined in the present disclosure.

[0055] In a 5G NR system, base stations (Transmission-Reception Points, TRPs) use massive antenna arrays comprising plural transceiving antenna elements that enable to efficiently use the MIMO (Multiple Input - Multiple Output) technology when a number of spatial MIMO streams or MIMO layers, which are to be transmitted simultaneously, are generated to transmit data (for example, the physical downlink data shared channel (PDSCH)).

[0056] A digital signal is transmitted or received by one or more digital ports coupled to antenna elements of a base station via a radio frequency unit which performs the function of forward and inverse conversion of the digital signal into an analog one. In particular, for the frequency range of 3.5 GHz up to 64 digital antenna ports can be employed which enable to use, in base stations, various precoding schemes. For instance, the spatial multiplexing (SM) technology enables to reuse the same time-frequency resources to transmit plural signals (MIMO layers) to one or more user devices (user equipments, UEs), while the adaptive beamforming technology enables to dynamically steer power of a transmitted signal into one or more predefined directions. Usage of advanced modulation techniques, such as orthogonal frequency-division multiplexing (OFDM), provides efficient broadband signal transmission. OFDM provides orthogonality of signals which are simultaneously transmitted on different subcarriers. Spatial MIMO layers are in general not orthogonal, and signals transmitted in different MIMO layers cause interference at a receiver side. As a rule, various adaptive beamforming techniques are employed in a receiver and in a transmitter to reduce the interference.

[0057] Furthermore, the transmitted MIMO layers are accordingly received by user devices which also support the abovementioned techniques.

[0058] Plural MIMO layers communicated from a base station can be transmitted to one UE, and this case refers to the single-user MIMO mode (SU-MIMO); or otherwise they can be transmitted to different UEs, and this case refers to the multi-user MIMO mode (MU-MIMO).

[0059] Reference signals (RSs) are used to enable communication between various devices in the 5G NR system, e.g. between base stations and user devices. A demodulation reference signal (DMRS) is one of such reference signals. DMRS signals are transmitted only within resources of a respective physical channel (in particular, the following physical data channels: PDSCH and physical uplink shared data channel (PUSCH)). In particular, a different DMRS signal is associated with each of simultaneously transmitted PDSCH / PUSCH spatial MIMO layers; moreover, the same adaptive precoding is used for a DMRS signal and a respective MIMO layer. In the 5G NR communication system, a unique index (number) referred to as DMRS port is associated with every DMRS signal. Therefore, for instance, a DMRS port is unambiguously mapped to every PDSCH spatial MIMO layer transmitted from a TRP in the 5G NR communication system; thus, the number of MIMO layers is equal to the number of DMRS ports.

[0060] The flow of transmission of plural spatial MIMO layers in combination with DMRS signals is illustrated in Fig.1.

[0061] Fig.1 provides a simplified scheme of the spatial processing in the transmitter, where signal adaptive precoding, which converts an input signal of MIMO layers into a signal of digital antenna ports, is performed in the first step. Furthermore, respective spatial processing in OFDM systems can be carried out in the frequency domain, thereby enabling to flexibly generate different beam patterns in different subcarriers. After the precoding procedure, the analog beamforming procedure is applied that converts a digital port input signal into signals of subarray physical antennas. The analog beamforming is performed in the time domain for the entire OFDM signal, thereby imposing constraints onto the number of simultaneously generated beams.

[0062] The main purpose of DMRS signals is providing coherent reception of physical data channels (PDSCH and PUSCH). More precisely, during propagation through a communication channel each of transmitted MIMO layers is subjected to various distortions, and the channel estimation procedure is performed at the receiver side to receive said MIMO layer, the algorithms of said procedure using a DMRS signal corresponding to the MIMO layer.

[0063] To transmit plural DMRS signals of respective MIMO layers, multiplexing of the signals over resource elements (REs) is used, where every RE is defined by a subcarrier in the frequency domain and an OFDM-symbol in the time domain. In the context of multiplexing DMRS signals in 5G NR, two types of DMRS patterns are supported: Type 1 DMRS pattern and Type 2 DMRS pattern. At most 8 DMRS signals are multiplexed in the Type 1 DMRS pattern, i.e. at most 8 DMRS ports are defined to transmit 8 spatial MIMO layers. At most 12 DMRS signals are multiplexed in the Type 2 DMRS pattern, i.e. at most 12 DMRS ports are defined to transmit 12 spatial MIMO layers.

[0064] Thus, maximum 12 spatial MIMO layers are supported in the 5G NR communication system at the TRP side. It should be also noted herein that, though up to 12 MIMO layers are generally supported at the TRP side, maximum 8 MIMO layers are supported in the SU-MIMO mode, i.e. not more than 8 MIMO layers can be simultaneously transmitted to one UE.

[0065] Then, Figs.2a-2c illustrate methods of allocating time resources in the 5G NR wireless communication system on the physical level.

[0066] The 5G NR system supports two types of allocating time resources for transmission of a physical data channel: Type A and Type B. In Fig.2a the former approach (Type A) is represented, wherein one downlink (DL) slot (DL slot) comprising 14 OFDM-symbols is a minimum unit of allocating time resources, i.e. a transmission time interval (TTI), to transmit the PDSCH. In a similar way, a TTI for transmitting the PUSCH is one uplink (UL) slot (UL slot). Type A is characterized by the limited capability of varying a start OFDM-symbol (from 0th to 3rd) of the data channel within a slot.

[0067] Type A is typically used for enhanced mobile broadband (eMBB) traffic, which corresponds, for example, to ordinary Internet traffic in smartphones.

[0068] Fig.2b illustrates the latter of the time resource allocation types used in 5G NR, in particular, Type B, wherein the TTI, i.e. granularity of a scheduled transmission duration, is a mini-slot. In this case, a user can be allocated, within a slot, with one or more PDSCH transmissions, each having length of one mini-slot comprising 2 (as shown in Fig.2b), 4, or 7 OFDM-symbols. A physical downlink control channel (PDCCH) is typically associated with each of such PDSCH transmissions; each mini-slot also comprises DMRS signals (not shown in Fig.2b). The same applies to PUSCH transmissions. This type, in particular, is characterized by greater flexibility of the data channel start symbol (from 0thto 12th) within a slot.

[0069] Type B is typically used for ultra-reliable low-latency communication (URLLC) traffic which is mostly used for communications in industrial applications (e.g. between robots etc.), where demands to fidelity / reliability and to latency are high.

[0070] Fig.2c illustrates an example of allocating time resources according to the Type A scheme over a greater time duration. This illustration generally relates to 5G NR time division duplex (TDD) systems where the same frequency band, but different time instants are used for downlink transmission and uplink transmission. In a TDD system, every frame having length of 10 ms is divided into a number of “downlink transmission - uplink transmission” periods (DL / UL-periods) each including a respective number of DL slots and UL slots separated by a guard interval (GI) to enable switching between DL and UL and for transmission in UL with timing advance. As seen from the illustrations of Figs.2a, 2c, in each DL / UL slot, OFDM-symbols are allocated for transmitting the PDCCH and DMRS signals. It should be noted that the ratio between the number of DL slots and UL slots in a DL / UL-period is flexibly configurable

[0071] In order to provide mutual one-to-one correspondence between transmissions sent from a TRP and received in an UE (and vice versa), the Hybrid Automatic Repeat Request (HARQ) procedure is supported. According to this procedure, a special index referred to as HARQ ID is assigned to each TTI both in uplink and downlink. As illustrated in Fig.2c, when scheduling, in the TRP, transmission of the PDSCH to the UE in a particular slot (e.g. the first from the left), the UE is informed in advance, by the PDCCH transmitted from the TRP, about HARQ ID of the transmission scheduled said slot. This informing is performed by downlink control information (DCI) carried in the PDCCH.

[0072] It should be noticed at this point that in the DCI the user device is also signaled about PDSCH / PUSCH signal transmission parameters chosen by a scheduler at the TRP side; information is communicated regarding indices of DMRS ports which are to be used for demodulation of transmitted PDSCH MIMO layers, as well as for PUSCH transmission; moreover, the DCI may include other control information, for example, information about a modulation and coding scheme (MCS), time domain resource allocation (TDRA), frequency domain resource allocation (FDRA), adaptive precoding, etc. The abovementioned informing by means of the DCI is relatively fast (in terms of low delays), since it is performed on the physical level; at the same time, transmission in the DCI message implies constraint on the amount of useable bits (not more than 50-70 bits in the 5G NR system).

[0073] When scheduling transmission of the PDSCH to the UE in one of subsequent slots (e.g. the third from the left), the UE is also informed by the DCI about HARQ ID of said transmission. As outlined above, the scheduler in the TRP schedules UL transmissions as well, and Fig.2c respectively illustrates that, when scheduling transmission of the PUSCH from the UE in a particular slot (e.g. the second from the right), the UE is informed by the DCI about HARQ ID of the transmission scheduled in said slot. It should be emphasized herein that in the considered case the scheduling of resources for the transmission is performed on the per slot basis.

[0074] If the UE successfully receives data with HARQ ID transmitted in the PDSCH, then the UE sends, in the physical uplink control channel (PUCCH) to the TRP, a positive acknowledgement (ACK) with respect to this transmission. If the UE receives data with HARQ ID with error in the certain slot, i.e. said data can not be successfully decoded in the UE, then the UE sends, by the PUCCH to the TRP, a negative acknowledgement (NACK) with respect to the transmission with HARQ ID . By means of the used HARQ mechanism, the TRP determines data which have not been correctly received in the UE and which therefore should be retransmitted, and the UE determines, with respect to every particular transmission, whether data being transmitted is new data or a retransmission of previously transmitted data. Retransmitted data are combined in the UE with previously received corresponding data which were decoded with error, and decoding is performed with respect to the combined data.

[0075] It should be emphasized once again that the exemplified configurations of a frame, slot, mini-slot are flexible in 5G NR to a substantial extent, and Figs.2a-2c are given solely as illustrations in order to provide exhaustive understanding of the present application. It should be further noted that the disclosure of Fig.2c given above equally applies to the case when mini-slots are used as TTIs.

[0076] The aspects of operating 5G NR wireless communication systems, as briefly discussed above, are disclosed in detail in specifications TS 38.211, 38.212 “NR; Physical channels and modulation”, v17.3.0, 2022-09-21, 3gpp.org, which are entirely incorporated into the present description by reference.

[0077] Though deployment of 5G NR systems in the world is only spinning up, nevertheless active research is being already carried out now in different directions for standardization of next generation wireless communication systems, so called 6G, which will have characteristics exceeding 5G NR.

[0078] In particular, for the 6G operating range of 10-13 GHz (UPPER MID BAND), it is planned to support, at base stations (TRPs), ultra-large antenna arrays, with at least 1024 antenna elements, hybrid analog and digital beamforming with a large number of antenna ports (≥ 128). Therefore, by supporting, in particular, up to 64 simultaneously transmitted spatial MIMO layers in UPPER MID BAND communication systems, the concept of radio interface with ultra-large antenna array (Extreme MIMO) will be rendered to a principally new level.

[0079] Support of a set of reference signals similar to the one used in 5G NR, such as DM-RS, CSI-RS, SRS, PT-RS, PSS / SSS, is planned in 6G. Details regarding the listed RSs are given in the abovementioned specifications. At the same time, the approaches to operating on the reference signals, as used in 5G NR, may not be always extrapolated to next generation wireless communication systems.

[0080] For instance, the abovementioned DMRS patterns used in 5G NR systems can enable to multiplex maximum 12 DMRS signals, whereas parallel transmission of at least 64 spatial MIMO layers and, hence, 64 DMRS signals should be provided in the 6G system. In other words, the existing DMRS patterns can not enable to multiplex the number of DMRS signals required for 6G. Therefore, new DMRS patterns to be designed for next generation communication systems (including 6G) should provide support of a greater number of DMRS ports (up to 64), besides other designed requirements to be satisfied thereby.

[0081] In this context it should be taken into account that, in view of the above requirement regarding increased capacity of the DMRS pattern (the capability of multiplexing a greater number of DMRS signals for a respectively greater number of MIMO layers), it will include a greater number of REs, inter alia - occupy a greater number of OFDM-symbols in the time domain. If the time resource allocation similar to 5G NR is used when doing this, then relatively high frequency of DMRS transmission, as typical to 5G NR, will unavoidably cause undesirably increased overhead in the case of the more capacious DMRS pattern.

[0082] Technical solutions are known from the art which relate to allocating resources in the time domain for future communication systems. Significant part thereof is based on using longer TTIs when scheduling transmissions. Such technical solutions are provided, for instance, in US 2019 / 0149365, US 10531452, US 9106418.

[0083] US 2019 / 0149365 provides methods for time domain resource allocations in wireless communications systems. Embodiments disclosed in US 2019 / 0149365 include time-domain symbol determination and / or indication using a combination of DCI and higher layer signaling for PDSCH and PUSCH; time domain resource allocations for mini-slot operations; rules for postponing and dropping for multiple mini-slot transmission; collision handling of sounding reference signals with semi-statically or semi-persistently configured uplink transmissions. The table based approach is substantially described to support configurable time-domain resource allocations. The drawback of the approach provided in US 2019 / 0149365 in the considered context is in that actual transmission should be aligned with the indicated time domain resource allocation, thereby resulting in increased complexity and latency.

[0084] In accordance with the technical solution provided in US 10531452, a mobile device may be scheduled for resources of multiple TTIs with a downlink control message, where some or all of the multiple TTIs may be associated with different HARQ processes. Each TTI may include data mapped to one transport block (TB), and each TB may be associated with a separate HARQ process. The downlink control message may include an indication of which HARQ processes are associated with resources of the multiple TTIs scheduled by the message. For example, the downlink control message may include a bitmap that indicates a relationship between each HARQ process and each TTI scheduled by the message. Feedback for TBs of some TTIs may differ, and an acknowledgment of receipt or successful decoding may depend on timing of TTIs in relation to a control message. Therefore, US 10531452 describes multi-TTIs scheduling with multiple HARQ process IDs per each TTI. The drawback of the approach provided in US 10531452 is in that the actual number of scheduled TTIs is aligned with the indicated TTIs in the control message, thereby causing increased complexity and latency.

[0085] US 9106418 discloses a method of transmitting data using HARQ that provides for early termination of an ongoing UL transmission with large number of repetitions. This solution is not applicable to high throughput services with long TTIs.

[0086] Hereinafter reference is made to exemplary embodiments of the present disclosure which are illustrated in the accompanying drawings where the same reference numerals denote similar elements. It should be appreciated that the embodiments of the disclosure can have various forms and should not be considered to be limited by the descriptions given herein. Therefore, the exemplary embodiments are described hereinbelow with reference to the drawings to elucidate the essence of the aspects of the present disclosure.

[0087] Fig.3 generally illustrates a wireless communication system wherein aspects of the present disclosure can be implemented. As shown in Fig.3, user devices (UEs) 301 communicate with base stations (TRPs) 302 in a radio access network (RAN) 300. UEs 301 (for example, UE 301-1, 301-2, 301-3, ...) are distributed over the RAN 300, and each of the UEs 301 can be fixed or mobile. Broadly known examples of UEs are smartphones, tablets, modems, etc.

[0088] The base stations 302 (for example, the TRPs 302-A, 302-B, 302-C) can provide coverage for a specific geographic area oftentimes referred to as ‘cell’. The base stations 302 basically have fixed structure, but they can have mobile implementation as well. In general, the base stations can represent macro-TRPs (as illustrated by the TRPs 302-A, 302-B, 302-C in Fig.3), as well as pico-TRPs for pico-cells or femto-TRPs for femto-cells. Cells in turn can be divided into sectors.

[0089] Coordination and management of operating the base stations 302 can be provided by a network controller which is in communication therewith (for instance, via a backhaul connection). The RAN 300 may be in communication with a core network (CN) (for example, via the network controller) which provides various network functions, such as e.g. access and mobility management, session management, authentication server function, application function, etc. Moreover, the base stations 302 in the RAN 300 can also connect to each other (for instance, via a direct physical connection).

[0090] When a user device is moving within the RAN 300, handover of the device from one TRP to another TRP can be performed. For example, the UE 301-3 can be handed over from the TRP 302-B to the TRP 302-A. While performing this, respective operation parameters of the UE are reconfigured for operation with the new TRP. The UE can be also handed over between sectors of one TRP.

[0091] In the 5G NR wireless communication system the Cloud RAN (C-RAN) concept is implemented that refers to dividing a base station into three parts and using a special interface defined to exchange information between these functional parts. In particular, the TRP can be divided into a radio unit (RU) which carries out radio transceiver functions, a distributed unit (DU) for L1 (physical level) and L2 (media access control (MAC) level) computations, and a centralized unit for L2 and L3 (radio resource control (RRC) level) computations. Such a division enables to centralize CUs in a respective central network node, whereas DUs can be distributed to a greater extent in cell nodes. In this case switchings of connections between cell nodes can be performed on the L1 level, i.e. with relatively small delays. Support of this concept is also expected in wireless communication networks of next generations.

[0092] It should be noticed that the description according to Fig.3 and said figure itself have exclusively illustrative, non-limiting nature with the aim of outlining the general operation environment of the present disclosure. Though only known basic components of the communication system are illustrated in Fig.3, it should be appreciated that the communication system can further include plural other elements.

[0093] Each of the TRPs 302 shown in Fig.3 includes hardware and logical means to implement respective functions in the TRP. The hardware means refer to, in particular, an antenna array comprised of transceiving antenna elements which have been discussed above, various specially configured processors, controllers, data storage devices, other circuit elements, as well as buses connecting them. The logical means refer to software which is stored in respective memory devices and configures respective circuit elements. Firmware directly hardwired in processors and controllers also refers to the software. The abovementioned hardware means are configured inter alia to perform various processing with respect to transmitted and received signals, including (de)modulation, (de)multiplexing, (de)coding, amplifying, filtering, digitizing, (de)interleaving, resource allocation, reception / transmission scheduling.

[0094] In a similar way, each of the UEs 301 shown in Fig.3 includes hardware and logical means to implement respective functions in the UE. The hardware means refer to, in particular, transceiving devices with respective antenna elements, various specially configured processor(s), controllers, data storage devices, other circuit elements, as well as buses connecting them. The logical means refer to software which is stored in respective memory devices and configures respective circuit elements. Firmware directly hardwired in controllers also refers to the software. The indicated hardware means are configured inter alia to perform various processing with respect to transmitted and received signals, including (de)modulation, (de)multiplexing, (de)coding, amplifying, filtering, digitizing, (de)interleaving. Moreover, the UE comprises means to interact with a user, including a touch screen, speakers / microphone, buttons, as well as user applications which are stored in the memory of the UE and executed by the processor of the UE in a respective operating system.

[0095] Examples of the abovementioned processors / controllers include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), discrete hardware integrated circuits, etc. Firmware / software executed by the processors / controllers should be understood broadly, as referring to computer-executable instructions, instruction sets, program code, code segments, subroutines, program modules, objects, procedures, etc. The software is stored in respective computer-readable media which can be implemented e.g. in the form of random-access memory (RAM), read-only memory (ROM), electrically erasable programmable (EEPROM), solid state storage devices, magnetic storage devices, optical storage devices, etc. which can be recorded with respective program codes and data structures that can be accessed by respective processors / controllers.

[0096] The hardware and software elements of TRPs and UEs, as listed above, are configured for enabling to perform, in the TRPs and UEs, the methods according to the present application which are described hereinbelow. Implementation itself of the component hardware means of the TRPs and the UEs and specific configuring thereof, including by respective logical means, is known in the technical field which the present application relates to. Moreover, various functions according to the methods of the present application can be performed in plural separate elements or in one or more integral elements, as defined by design structural characteristics.

[0097] In view of the aforesaid when describing the background art, increased capacity of the new DMRS pattern for next generation (including 6G) wireless communication systems causes such a pattern to occupy a greater number of OFDM-symbols in the time domain. If allocation of time domain resources according to 5G NR is used in this case, for example, according to Type A described with reference to Figs.2a, 2c, then the presence of the more capacious DMRS pattern along with the control channel in every slot will lead to undesired growth of overhead. This aspect is pictorially illustrated in Fig.4 from the right part of which it is seen that only 4 OFDM-symbols remain in the slot for 6G PDSCH transmission.

[0098] It should be reminded herein that, in 5G NR Type A, allocation of at least one OFDM-symbol for a DMRS signal(s) in every slot is typically required. Therefore, the DMRS signal will be transmitted to an UE with every slot, even if no changes in distribution of DMRS ports have taken place; moreover, at least one symbol is occupied by the control channel in every slot.

[0099] Hereinafter, improved techniques of allocating time domain resources, which would enable to avoid this negative effect, are accordingly discussed.

[0100] First, the general aggregated approach to allocating resources in the time domain, both on the slot level and the mini-slot level, is disclosed with reference to Figs.5-8.

[0101] As in the case of 5G NR, from the macro view, a frame of length 10 ms is divided in a plurality of the same DL / UL-periods, wherein length of a DL / UL-period is configurable in a base station. The base station can signal the set DL / UL-period length to UEs served thereby by using the abovementioned DCI (L1) signaling, MAC (L2) signaling, RRC (L3) signaling, or even some combination thereof. Every DL / UL-period is split into slots, where every slot can consist of 14 or 12 (if the extended cyclic prefix is used in the slot) OFDM-symbols.

[0102] Typically, a part of slots of a DL / UL-period is allocated for downlink (DL) transmission (a DL-part), while another part of slots of the DL / UL-period is allocated for uplink (UL) transmission (an UL-part). The DL-part and the UL-part are separated from each other by a guard interval (GI) to provide time for switching between the DL transmission and the UL transmission and UL transmission with timing advance. Part of a slot of the DL-part or of the UL-part is usually allotted for the guard interval. It should be noticed that distribution of slots between the DL- and UL-parts is configurable in the base station - for instance, all OFDM-symbols of the DL / UL-period can be allocated only for the DL-part.

[0103] In accordance with the general approach of the present application, aggregation of slots or mini-slots is carried out, so that a larger unit is utilized for allocating / scheduling resources in the time domain than a single slot (Type A in 5G NG) or a single mini-slot (Type B in 5G NG). That is, it is assumed that allocation of resources in the time domain for transmitting data can be performed in such aggregated units.

[0104] Exemplary embodiments of the aggregation for the DL-part of a DL / UL-period of a frame will be described first with reference to Figs.5a, 5b.

[0105] Fig.5a shows, along the time axis, OFDM-symbols which constitute three slots of the DL-part of the DL / UL-period. These slots are aggregated into a single bundle of slots which forms the new unit of scheduling / allocating time domain resources (TTI). Unlike the respective 5G NR Type A (see Fig.2a), adjacent OFDM-symbols allocated for transmission of the physical downlink control channel (PDCCH) are allocated per entire slot bundle rather than per every slot, as in the case of 5G NR Type A.

[0106] One or more adjacent OFDM-symbols are also allocated for transmission of a DMRS pattern; such a combination of adjacent symbols will be referred to hereinafter as a DMRS-subbundle. DMRS signals for a required number of MIMO layers of the PDSCH to be transmitted are multiplexed in the DMRS pattern. As a non-limiting example, one of the advanced DMRS patterns described in detail in patent RU2801697, whose disclosure is implied to be fully incorporated by reference into the specification of the present application, can be used herein as a DMRS pattern oriented towards next generation communication systems.

[0107] It should be emphasized that the allocation of DMRS-subbundles, as shown Fig.5a, is illustrative, and other allocations thereof can be used. Then, the DMRS-subbundle size of 4 OFDM-symbols, as shown in Fig.5a, does not impose any limitations either. The aspects of allotting DMRS-subbundles are described in patent RU2801697.

[0108] The remaining OFDM-symbols in the slot bundle can be allocated for transmission of the PDSCH. Though Fig.5a shows allocation of all the remaining symbols, it should be appreciated that a smaller number thereof can be allocated for the PDSCH transmission as well, which will be discussed in more detail below. Then, every slot in Fig.5a is shown comprising 14 OFDM-symbols; at the same time, as recited above, a slot can comprise 12 OFDM-symbols. The indicated specific aspects do not impose any limitations onto the disclosure disclosed herein.

[0109] Fig.5b shows, along the same time axis, OFDM-symbols which constitute four mini-slots of the DL-part of the DL / UL-period, each mini-slot comprising 4 OFDM-symbols. These mini-slots are aggregated into a single bundle of mini-slots which also forms a new unit of scheduling / allocating time domain resources (TTI). Unlike the respective 5G NR Type B (see Fig.2b), adjacent OFDM-symbols of the physical downlink control channel (PDCCH), like in the case of Fig.5a, are allotted per entire mini-slot bundle rather than per every mini-slot, as in the case of 5G NR Type B. The attention should be drawn to the fact that in the considered example adjacent OFDM-symbols allocated for transmission of the PDCCH precede the mini-slot bundle, being not included thereby. This does not impose any limitation, and the mini-slot bundle can be arranged including the PDCCH OFDM-symbols.

[0110] Similarly to the discussion according to Fig.5a, a DMRS-subbundle can be also allotted in the mini-slot bundle for transmission of DMRS signals. In this case, solely for the sake of illustration, the DMRS-subbundle is shown occupying the entire mini-slot within the mini-slot bundle that follows after the PDCCH symbols.

[0111] The other OFDM-symbols in the mini-slot bundle can be allocated for transmission of the PDSCH. Though Fig.5b shows allocation of all the other symbols, it should be appreciated that a greater or smaller number thereof can be allocated for the PDSCH transmission.

[0112] Then, every mini-slot in Fig.5b is shown comprising 4 OFDM-symbols; at the same time, as outlined above, a mini-slot can be also comprised of 2 or 7 OFDM-symbols, and the DMRS-subbundle itself can have a different size, as recited with respect to Fig.5a, and may not be aligned with boundaries of a mini-slot. The indicated specific aspects do not impose any limitations onto the disclosed disclosure.

[0113] The mini-slot length is in general set in a TRP and signaled from the TRP to UEs through a control message. For example, an RRC message or a DCI message can be used to indicate the mini-slot length. A combination of RRC and DCI messages can be also used, when the RRC message specifies a subset of mini-slot length values: for example, the subset {2, 7} is specified from the entire set {2, 4, 7, 14}, while the DCI message indicates one specific value from said subset (for instance, 1 bit in the DCI selects either 2 or 7) which relates to the current PDSCH signal transmission.

[0114] Figs.6a, 6b show a macro view of the considered general approach to aggregation.

[0115] Fig.6a shows the case when a bundle of slots or mini-slots occupies the entire DL-part, and Fig.6b illustrates the case when a bundle of slots or mini-slots is preceded by a slot. It should be emphasized for the embodiment of Fig.6b that the abovementioned OFDM-symbols for the PDCCH are included by the preceding slot, at the same time, said PDCCH contains control information for scheduling the bundle of slots / mini-slots. In other words, the presence of the PDCCH OFDM-symbols in the slot bundle, as depicted in Fig.5a, is not mandatory according to the present application. The embodiment of Fig.6b can be considered as corresponding to the combination of the known approach (5G NR Type A) and the general approach to aggregating time resources considered herein. It should be also appreciated that the bundle of slots / mini-slots can be preceded by more than one slot; moreover, an embodiment is possible when the bundle of slots / mini-slots precedes one or more slots.

[0116] It should be explained that, in accordance with the general approach being discussed, the PDCCH can reside, in general, in any place of the DL / UL-period according to the configuration of decoding of the control channel. The principal requirement is that, for a specific UE, transmission of the PDCCH takes place prior to the beginning of the bundle of slots / mini-slots, so that the UE is able to receive the control channel and decode the DCI which will contain information about scheduling of the PDSCH (including information about the beginning of transmission of the bundle of slots / mini-slots and duration of said bundle).

[0117] Reduced overhead is clearly seen from the illustrations according to Figs.6a, 6b - in particular, reservation of an OFDM-symbol(s) for the PDCCH for every slot / mini-slot is avoided; furthermore, the possibility of using less frequent DMRS occasions within the DL / UL-period, without reduction of the channel estimation quality, is provided.

[0118] As noted above, scheduling of time domain resources to transmit data is performed by a scheduler of a base station (TRP), and UEs are informed about the resources reserved by the scheduler via the downlink control channel transmitted from the TRP. In accordance with the present disclosure, a bundle of slots or mini-slots can be used as a unit of scheduling / allocating time domain resources for transmission, unlike a single slot or mini-slot according to 5G NR. The aggregation configuration according to the present application is set by the base station (TRP), and information about said configuration (in particular, an indication of the beginning of the bundle of slots / mini-slots in the DL / UL-period and duration of said bundle) is signaled to UEs in the PDCCH. According to the preferred embodiment, said information is at least partially transmitted in the DCI message carried in the PDCCH. It should be noted that the DCI can further signal other control information which has been mentioned above.

[0119] The start OFDM-symbol of the bundle of slots / mini-slots within the DL / UL-period can be indicated in the DCI as the beginning of said bundle. The length of the bundle of slots / mini-slots is set in the TRP as a function of a scheduler decision which may depend on a size of data transmitted to a user, the necessity to transmit data to another user, a transmitted traffic type, a channel state (modulation, coding rate, a number of MIMO layers), transmission of other scheduled signals, etc.

[0120] Then, channel coding is typically performed with respect to data to be transmitted in the PDSCH. Channel coding is block coding, and encoded data is represented as a result as code blocks of certain length. LDPC (low density parity check) coding can be a possible embodiment of channel coding. The code blocks are then respectively mapped to time-frequency and spatial resources for transmission in the PDSCH. Each code block is mapped to time-frequency and spatial resources as a whole.

[0121] Moreover, if the existing procedure of determining the number of code blocks for data transmission, as disclosed in TS 38.212 5G NR, is directly applied when mapping code blocks to time-frequency resources, then said procedure should be applied to the entire bundle of slots / mini-slots according to the present disclosure (for example, to the entire DL-part of the DL / UL-period), and, as a consequence, alignment of temporal boundaries of an integer number of code blocks will be ensured only by the end of such a bundle of slots / mini-slots. That is, if the existing approach is directly used, then alignment of temporal boundaries of an integer number of code blocks with a slot or mini-slot boundary will not be ensured, in general. As a consequence, processing of received data can not start at the receiver side until the entire aggregated bundle of slots / mini-slots is received. In other words, a downtime occurs at the receiver side, said downtime being associated with the necessity of buffering the received code blocks while waiting for the end of reception of the aggregated bundle, so that the processing of said code blocks could begin.

[0122] The general approach to aggregating time domain resources, as being discussed herein, enables to resolve this problem and improve efficiency of pipelining of the code block processing at the receiver side, which is illustrated in Fig.7.

[0123] In accordance with the preferred embodiment, the number and length of code blocks are selected according to a mini-slot length in such a way that, when allocating time-frequency resources for every combination of said number of code blocks, boundaries of this combination in the time domain are aligned specifically with mini-slot boundaries in a mini-slot bundle. More particularly, the number and length of code blocks are selected according to the number of available REs in a mini-slot, modulation being used, and channel coding rate. Moreover, in the considered embodiment, usage of said existing procedure of determining the number of code blocks, as described in TS 38.212 5G NR, is substantially performed specifically with respect to each group of OFDM-symbols which form a mini-slot, individually.

[0124] Fig.7 shows alignment of sets of three code blocks with boundaries of mini-slots in a mini-slot bundle. As a consequence, data processing in the receiver can start almost immediately upon reception of the first mini-slot comprising three (i.e. integer number) of code blocks; then, upon reception of the second mini-slot, the processing of the next three code blocks will be performed; etc. It should be obvious that, in the considered embodiment, downtimes associated with the processing of the received data, are significantly reduced. Attention should be also drawn to high flexibility of the considered embodiment, since, besides the length and number of code blocks, the mini-slot duration is itself flexibly configurable.

[0125] It should be emphasized that, though the embodiment described above is preferable for the mini-slot-level aggregation, it is nevertheless equally applicable to slot-level aggregation. In view of the aforesaid, it should be obvious for the slot-level implementation that a greater delay will take place than in the illustrated case of mini-slots.

[0126] The techniques of aggregating time domain resources according to the present application, as described with reference to Figs.5-7 with respect to the DL-part of the DL / UL-period of the frame, apply to its UL-part as well. In this case the specificity is in that the TRP scheduler decision is single with respect to both the DL-part and the UL-part, and information regarding allocation of time domain resources for the UL-part is also signaled in the physical downlink control channel (PDCCH), as discussed above. For instance, the beginning and duration of transmission of an UL bundle of slots / mini-slots is selected in the TRP and signaled to the UE by the control information in the PDCCH; more particularly, said selection is performed by the TRP scheduler, and said signaling is performed through the DCI in the PDCCH.

[0127] Therefore, an uplink control channel, which is the PUCCH in the considered case, will in general have different functionality as compared to the downlink control channel. In particular, in the UL-part, there is no mandatory requirement for the control channel to precede the DMRS and PUSCH; furthermore, the uplink control channel may be absent at all in the UL-part.

[0128] For instance, in Figs.6a, 6b, exclusively for the sake of illustration, the PUCCH is shown as located in the tail of the bundle of slots / mini-slots and containing acknowledgement (ACK / NACK) information. Nevertheless, in the UL-part, OFDM-symbols allocated for the PUCCH may precede OFDM-symbols allocated for the DMRS and PUSCH. It should be emphasized that, in general, the bundle of slots / mini-slots according to the present disclosure may be substantially in any place of the UL-part.

[0129] Since the PUCCH is not directly associated with resource scheduling, then options are possible when transmission of the PUCCH will not relate anyhow to a bundle(s) of slots / mini-slots (neither to slots or mini-slots at all) - for example, said channel can be used to transmit a Scheduling Request or Channel State Information (CSI), - or when transmission of the PUCCH will relate to preceding slots, mini-slots, or a bundle(s) of slots / mini-slots.

[0130] Then, an embodiment of the method 800 of aggregated allocation of resources in the time domain in accordance with the general approach according to the present application is described hereinafter with reference to Figs.8a, 8b. As an illustration, the method 800 is performed in a base station (for example, the TRP 302 in Fig.3).

[0131] Steps 810-860 of the method 800, which are performed with respect to a DL-part of an DL / UL-period of a frame, are considered with reference to Fig.8a.

[0132] In step 810, a preset number of adjacent OFDM-symbols are allocated for transmission of the PDCCH.

[0133] In step 820, a DL bundle of time intervals is generated, the bundle comprising an integer number of adjacent time intervals, wherein each time interval includes a preset number of OFDM-symbols. Moreover, the PDCCH, which is to be transmitted in the OFDM-symbols of the DL-part that have been allocated thereto, relates to the entire bundle of time intervals. In accordance with the above disclosure, the time interval can be a slot which can comprise 12 or 14 OFDM-symbols, or a mini-slot which can comprise 2, 4, or 7 OFDM-symbols.

[0134] In step 830, at least one DL DMRS-subbundle is allocated to transmit DMRS signals for a required number of MIMO layers of the PDSCH.

[0135] In step 840, OFDM-symbols for transmission of the PDSCH are allocated in the DL bundle of time intervals.

[0136] The possible embodiments of mutual arrangement of OFDM-symbols for the PDCCH, the DL DMRS-subbundle(s), and the bundle of slots / mini-slots in the DL-part are indicated above, in particular, with reference to Figs.5, 6.

[0137] In step 850, the DL bundle of time intervals is allocated for the scheduled DL transmission.

[0138] As reported above multiple times, the control information should be transmitted in the PDCCH, more specifically - in the DCI message. Besides the control data which have been outlined above, in the considered case the control information can include an indication of the beginning of the DL bundle of time intervals and a duration of the DL bundle of time intervals.

[0139] In step 860, for data to be transmitted in the OFDM-symbols allocated for the PDSCH in the DL bundle of time intervals, a size and a number of code blocks are determined to perform channel coding (preferably, LDPC), and code blocks representing the encoded data are obtained. The number and the length of the code blocks are selected in such a way that, when allocating time-frequency resources for every combination of said number of code blocks, boundaries of said combination in the time domain are aligned with boundaries of a time interval in the bundle of time intervals (see Fig.7).

[0140] Steps 870-875 of the method 800, which are performed with respect to an UL-part of the DL / UL-period of the frame, are considered with reference to Fig.8b.

[0141] In step 870, an UL bundle of time intervals which comprises an integer number of time intervals is generated.

[0142] In step 871, at least one UL DMRS-subbundle is allocated to transmit DMRS signals for a required number of MIMO layers of the PUSCH.

[0143] In step 872, OFDM-symbols for transmission of the PUSCH are allocated.

[0144] In step 873, a preset number of adjacent OFDM-symbols are allocated for transmission of the PUCCH.

[0145] The possible embodiments of mutual arrangement of OFDM-symbols for the PUCCH, the UL DMRS-subbundle(s), and the bundle of slots / mini-slots in the UL-part are described above.

[0146] In step 874, the UL bundle of time intervals is allocated for the UL transmission.

[0147] In step 875, similarly to step 860, channel coding, along with respectively selecting a number and a length of code blocks, is performed with respect to data to be transmitted in the OFDM-symbols allocated for the PUSCH in the UL bundle of time intervals.

[0148] It should be appreciated that the general approach to time resource allocation, as proposed herein, is applicable to various advanced DMRS patterns which are planned for being used in next generation wireless communication systems.

[0149] Though the aggregation technique described above with reference to Figs.5 to 8 provides the advantage which is significant in the context of next generation communication system and which relates to reduced overhead by avoiding the necessity of reserving an OFDM-symbol(s) for the control channel for each slot / mini-slot, as well as by enabling to use less frequent DMRS transmissions without decrease in channel estimation quality, nevertheless, usage of said technique as such causes certain drawbacks.

[0150] In particular, since the scheduler in the TRP is required to operate on the level of a slot / mini-slot bundle, i.e. a longer TTI than an individual slot or mini-slot, then implementation of scheduling performed thereby becomes more complex; for instance, buffering of greater amount of data is required prior to the scheduler takes a decision.

[0151] Moreover, an undesired delay may occur, and the nature of the delay is explained hereinbelow with reference to Fig.9. It should be first of all noticed herein that Fig.9 as a whole corresponds to Fig.6b. It should be also explained that vertical dashed lines shown in the slot / mini-slot bundle (SB / MSB) in Fig.9 respectively denote slots / mini-slots which said bundle is aggregated from.

[0152] As discussed above, in particular, with reference to Figs.5 to 8, scheduling of transmission of the PDSCH can be performed in the TRP with granularity of one SB / MSB, and a decision of the scheduler regarding the scheduled transmission, as well information about the beginning and duration of the SB / MSB, are reflected in the DCI which is to be sent in advance to the UE via the PDCCH. As a result, since the UE perceives the entire allocated SB / MSB of the preliminarily signaled duration as actual transmission of the PDSCH, even when data destined to the UE in fact occupies only part of said SB / MSB, then the TRP in turn will be unable to use a vacant part(s) of the SB / MSB to send, by the PDSCH, data which arrived for being transmitted after said DCI had been generated for the UE. Ultimately, having available time resources, the TRP will have to wait for a next DCI occasion to schedule transmission of said newly arrived data, i.e. at least - for the end of said SB / MSB (moreover, this occasion may occur only in the next DL / UL-period). As a consequence, the delay and insufficiently efficient usage of time resources takes place.

[0153] The present disclosure is specifically directed towards removing this drawback and, accordingly, towards improved efficiency of using time resources when aggregating them according to the general approach described above.

[0154] The approach according to the present disclosure, which provides more flexible allocation of time domain resources in the considered context, is described below with reference to Figs.10 to 15.

[0155] Figs.10a, 10b provide a general illustration of allocation of time domain resources according to the present disclosure.

[0156] Similarly to the case according to Figs.6a, 6b, 9, the base station (TRP) carries out pre-allocation of a slot / mini-slot bundle, i.e. a TTI, of a predetermined duration to transmit data by the PDSCH to a user device (UE). Vertical dashed lined in Figs.10a, 10b also denote slots or mini-slots which the considered TTI is generated from. Each of such slots or mini-slots respectively comprised by the TTI can be generally referred to as sub-TTI throughout the text of the present application. The beginning and end of the pre-allocated slot / mini-slot bundle are respectively aligned with slot / mini-slot boundaries. As in the case of 5G NR, a HARQ ID is associated with each sub-TTI in the bundle (denoted as , in Fig.10a). Furthermore, the approach to arranging data code blocks with improved pipelining is implied in the considered case, as described above with reference to Fig.7 (see also step 860 in Fig.8a and step 875 in Fig.8b). Finally, it should be also elucidated that the illustrations according to Figs.10 to 14 correspond to scheduling transmission of the PDSCH to a particular UE.

[0157] The base station generates DCI which reflects data regarding the pre-allocated TTI. Besides said indication of the beginning and duration of the TTI, the data also includes information enabling to determine, at the UE side, HARQ IDs of all the sub-TTIs of the pre-allocated TTI. As an option, said information can directly represent the entire array of the HARQ IDs of those sub-TTIs, i.e. , in Fig.10a. Otherwise, said information can represent auxiliary data based on which the HARQ IDs of all the sub-TTIs of the TTI pre-allocated in the TRP to transmit the PDSCH can be calculated at the UE side, for example, with account of the beginning and duration of the TTI which are signaled in the DCI. As reported previously, the indication of the beginning of the TTI can be an indication of its start OFDM-symbol, whereas the indication of the duration of the TTI is preferably an indication of the number of sub-TTIs in the TTI, or, as an option, it may be an indication of an end OFDM-symbol of the TTI. It should be emphasized that the specificity of signaling the beginning and end of the TTI and HARQ IDs to the UE, as described in the present paragraph, does not impose limitations onto the present disclosure, and other known approaches can be used. It should be also noticed that, in accordance with the aforesaid, the other control information, including the one with respect to scheduling of UL transmission, is also included in the DCI.

[0158] The generated DCI is transmitted from the TRP to the UE by the PDCCCH for which the predetermined number of adjacent OFDM-symbols have been allocated in the TRP in the DL-part of the DL / UL-period (see step 810 in Fig.8a). Therefore, the entire TTI turns out to be reserved for transmission of the PDSCH to the UE, and the UE is informed about it in the way outlined above.

[0159] In accordance with the present disclosure, the base station (TRP) is enabled to begin and end actual data transmission through the PDSCH within the reserved TTI in a flexible way, substantially - at its own discretion. In Fig.10b actual transmission of the PDSCH is shown as starting in the first sub-TTI of the reserved TTI and ending before expiration of the TTI; in Fig.10b actual transmission of the PDSCH is shown as starting upon lapse of plural sub-TTIs from the beginning of the reserved TTI and ending again before expiration of the TTI. In any case, the beginning and end of actual transmission of the PDSCH are matched to slot or mini-slot boundaries representing a sub-TTI, i.e., for example, the mention of the beginning of actual transmission as ‘at own discretion’ refers herein to a beginning of any suitable sub-TTI in the TTI. In other words, in the considered case the situation takes place that actual transmission of the PDSCH occupies not all time resources reserved for it, i.e. the reserving has been performed with overbooking. According to the present disclosure, the UE is informed post factum about particular sub-TTIs in which actual transmission of the PDSCH was performed, and this will be described in detail below.

[0160] At such a flexible approach to start / end of actual transmission of the PDSCH in the base station, the plurality of HARQ IDs of the reserved TTI is substantially divided into two sub-pluralities: , where is a sub-plurality of HARQ IDs of sub-TTIs in which actual transmission of the PDSCH to the UE is performed (denoted in Figs.10a, 10b and in the left part of Fig.11 by solid ellipses), and is a sub-plurality of HARQ IDs of sub-TTIs in which actual transmission of the PDSCH to the UE is not performed (denoted in Figs.10a, 10b and in the left part of Fig.11 by dotted ellipses). The sub-plurality substantially represents a margin of time resources within the reserved TTI that can be used, as enabled by the present disclosure, by the TRP for other transmissions, for example, transmission of new data to another UE (see the indication in Fig.10b). The UE is aware herein of said division neither when reserving the TTI, nor in the following transmission performed from the TRP during said TTI.

[0161] At the UE side, reception of data is being performed during the entire TTI initially reserved for the transmission, and received data from each sub-TTI of said TTI is placed into the buffer, thereafter an attempt to decode said data is made in the UE.

[0162] As discussed above when describing 5G NR, if data is decoded successfully, it is forwarded to subsequent processing performed in the UE, and a positive acknowledgement (ACK) is sent from the UE to the TRP with respect to HARQ ID of the sub-TTI in which said data was transmitted (see Fig.10b). This acknowledging is preferably implemented by the PUCCH. Though Fig.10b shows transmission of the PUCCH in the same DL / UL-period as the transmission of the PDSCH, this does not impose limitations onto the present disclosure - for instance, PUCCH transmission may be absent in the considered DL / UL-period, and it can be carried out in some of subsequent DL / UL-periods.

[0163] In 5G NR, it is quite clear at the UE side that all time resources reserved for the UE are to carry payload data, and unsuccessful decoding of data from some slot or mini-slot would unambiguously indicate to the UE that transmission of said data was performed with error. As a result, this ‘erroneous’ data is left in the buffer of the UE, and a negative acknowledgement (NACK) is sent in a similar way to the base station in the PUCCH, thereby requesting the base station to retransmit the data for said slot or mini-slot. By means of HARQ IDs, the base station knows for which slot / mini-slot retransmission of data is required. Received retransmitted data is combined in the UE with the respective data maintained in the buffer, and decoding is performed with respect to the combined data.

[0164] Since, according to the present disclosure, decoding, in the UE, of data from any sub-TTI which is not used in the reserved TTI for actual transmission of the PDSCH to the UE (i.e. a sub-TTI with HARQ ID from the sub-plurality ) must complete unsuccessfully, then in the present disclosure there is initially an uncertainty at the UE side on whether unsuccessfully decoded data is ‘erroneous’ data, i.e. payload data which was transmitted with error, or ‘garbage’ data, i.e. data from a sub-TTI which is not used for actual transmission of the PDSCH, for example, it is used to transmit other signals. In other words, the UE currently does not known in which particular sub-TTIs actual transmission of the PDSCH is performed. Nevertheless, as in 5G NR, any unsuccessfully decoded data remains in the buffer in the UE, and NACK is transmitted in the PUCCH to the base station with respect to HARQ ID of the sub-TTI in which said data was transmitted. Once again, as in 5G NR, if NACK is transmitted to the base station with respect to a sub-TTI with HARQ ID from the sub-plurality , i.e. an error occurred when transmitting payload data by the PDSCH, then the base station will subsequently retransmit said data to the UE, and in the UE the retransmitted data will be combined with the data from the buffer that corresponds to said sub-TTI, and decoding of such combined data will be performed.

[0165] As discussed above, according the present disclosure, the UE is post factum informed about sub-TTIs of the reserved TTI in which actual transmission of the PDSCH was not performed.

[0166] In accordance with the present disclosure, two options of such informing are provided - explicit informing and implicit informing.

[0167] In the case of explicit informing which is illustrated in the right part of Fig.11, the base station transmits, within subsequent DCI, all HARQ IDs of the sub-plurality , i.e. identifiers of sub-TTIs of the previously reserved TTI in which transmission of the PDSCH to the UE was not performed. As an alternative, the sub-plurality of HARQ IDs can be instead reported in the subsequent DCI, and, since the UE is aware of HARQ IDs of all the sub-TTIs, the UE will readily identify the sub-plurality based on this report. It should be appreciated that a reference to ‘subsequent DCI’ herein does not imply the limitation to specifically the DCI whose transmission directly follows the transmission of the DCI used for reserving the TTI (see Figs.10a, 10b, left part of Fig.11) - it should be evident to a skilled artisan that the transmission of such subsequent DCI may be preceded by transmission of at least one other DCI.

[0168] As seen from the right part of Fig.11, the subsequent DCI transmitted in the PDCCH, similarly to the illustration shown in Figs.10a, 10b and in the left part of Fig.11, is also used for reserving time resources with overbooking for subsequent PDSCH transmission, along with similarly assigning slots / mini-slots with HARQ IDs from the plurality and virtually dividing said plurality into the respective sub-pluralities , .

[0169] Furthermore, in the UE, upon reception of the subsequent DCI, all data corresponding to sub-TTIs with reported HARQ IDs from the sub-plurality , are removed from the buffer.

[0170] The implicit informing of the UE according to the present disclosure is implemented based on timers, without directly reporting respective HARQ IDs from the base station.

[0171] According to one embodiment of the present disclosure, upon transmission of the DCI with information about the reserved TTI (see Figs.10a, 10b, left part of Fig.11), a timer of a predefined duration is started in the base station, and a timer of the predefined duration is started in the UE upon reception of said DCI. Of course, the start of the timer in the UE is performed with due account for the time of signal propagation between the base station and the UE. The timer duration is set in the base station and signaled to the UE in advance (i.e. prior to the start), preferably by MAC signaling or RRC signaling.

[0172] The timer duration is initially set in such a way that, with respect to all payload data from sub-TTIs with HARQ IDs from the sub-plurality which the UE failed to decode and for which NACKs were sent to the base station from the UE, the base station will unambiguously manage to complete retransmission to the UE, and the UE will manage to complete decoding of respective combined data. As a result, upon expiration of the timer in the user device, all data which reside in the buffer and for which retransmitted data have not been received from the base station within the timer duration will be identified by the user device as ‘garbage’, i.e. as data from sub-TTIs with HARQ IDs from the sub-plurality ,and said data will be removed from the buffer of the user device. Therefore, the expiration of the timer in the considered context implicitly informs the UE about HARQ IDs of sub-TTIs of the initially reserved TTI which were not used for actual transmission of data to the UE by the PDSCH.

[0173] Another, alternative embodiment of the implicit informing of the UE is substantially similar to the embodiment described above, except for associating, in the TRP and in the UE, an individual timer of the same predefined duration with each sub-TTI of the reserved TTI and accordingly starting said timer. More specifically, upon completion of transmission of data in each sub-TTI, the individual timer of the predefined duration in started in the base station, and the individual timer of said duration is started in the UE upon reception of the data in said sub-TTI. In thus embodiment, the start of the timer in the UE is performed with account of the time of signal propagation between the TRP and the UE.

[0174] Similarly to the former embodiment where the timer is started based on the DCI, if, for some sub-TTI, NACK was sent from the UE to the TRP due to unsuccessful decoding of data received in the sub-TTI and respective retransmitted data were not received from the TRP within the timer duration, then, upon expiration of the timer in the UE, said sub-TTI will be by default identified as a sub-TTI with HARQ ID from the sub-plurality . Once again, all ‘garbage’ data corresponding to the sub-TTIs identified in such a way are removed from the buffer of the UE.

[0175] Hereinafter, disclosure is provided with reference to Figs.12-14 for an embodiment of operating with pluralities of HARQ IDs at the TRP side and at the UE side in implementation of the present disclosure whose embodiments have been disclosed above with reference to Figs.10-11. Fig.12 corresponds to the general scheme of exchanging transmissions between the TRP and the UE according to the present disclosure, Fig.13 shows respective actions performed in the explicit informing according to the present disclosure, and Fig.14 shows respective actions performed in the implicit informing according to the present disclosure.

[0176] The TRP maintains a plurality of available HARQ IDs, and the UE maintains a plurality of used HARQ IDs.

[0177] As disclosed previously with reference to Figs.10-11, the TRP initially pre-allocates the TTI with overbooking to transmit the PDSCH to the UE, along with assigning HARQ ID ( herein substantially denotes an order index of a sub-TTI) to each sub-TTI (i.e. a slot or mini-slot) which said TTI is aggregated from, and reserves this TTI by transmitting, to the UE in the PDCCH, the DCI including information about the reserved TTI. Fig.12 illustrates transmission, in the DCI, of an array of HARQ IDs of all the sub-TTIs of the reserved TTI.

[0178] Furthermore, upon the reserving, the plurality is excluded in the TRP from the plurality of available HARQ IDs , reference numeral 1 in Figs.13, 14. In general, the plurality of available HARQ IDs corresponds to sub-TTIs which can be used in the TRP to transmit new (i.e. not retransmitted) data, while the plurality of used HARQ IDs corresponds to sub-TTIs wherefrom data received are in the buffer in the UE. Since, in accordance with the aforesaid, data from all the sub-TTIs of the reserved TTI must be buffered in the UE, then, upon reception of the DCI, said plurality is added to the plurality of used HARQ IDs in the UE: , reference numeral 1 in Figs.13, 14.

[0179] Then, in accordance with the disclosure of Figs.10-11, the TRP carries out actual transmission of the PDSCH to the UE in the subset of sub-TTIs of the reserved TTI, having the capability to flexibly set the beginning and end of said actual transmission. Moreover, as outlined above, the plurality of HARQ IDs is virtually divided at the TRP side into the two sub-pluralities: , where is the sub-plurality of HARQ IDs of sub-TTIs in which actual transmission of the PDSCH is performed, and is the sub-plurality of HARQ IDs of sub-TTIs which are not used for actual transmission of the PDSCH (in which ‘garbage’ data are transmitted, from the UE’s point of view); at this time, this division is currently not known at the UE side. In Fig.12 this transmission is depicted as transmission of the PDSCH in sub-TTIs with HARQ IDs from the sub-plurality .

[0180] The UE places into its buffer received data from each sub-TTI of the reserved TTI, and performs decoding of said data. If decoding of buffered data corresponding to some sub-TTI with HARQ ID is completed successfully, then said data is removed from the buffer, and the UE sends ACK through the PUCCH to the TRP with respect to the sub-TTI with HARQ ID . The plurality of HARQ IDs, which have been positively acknowledged in such a way, is excluded from the plurality of used HARQ IDs in the UE: , reference numeral 2 in Figs.13, 14. At the same time, the plurality of available HARQ IDs in the TRP is added with this plurality , reference numeral 2 in Figs.13, 14. The UE transmits NACK with respect to each of sub-TTIs which contained payload data transmitted with error (i.e. sub-TTIs with HARQ IDs from the sub-plurality ) and with respect to sub-TTIs which contained ‘garbage’ data for the UE (i.e. sub-TTIs with HARQ IDs from the sub-plurality ), and corresponding data remains in the buffer of the UE.

[0181] Then, in accordance with the disclosure according to Figs.10-11, in the case of the embodiment with the explicit informing, the TRP sends, within subsequent DCI, infromation about the sub-plurality of HARQ IDs identifying sub-TTIs which were not used in the respective previosuly resserved TTI for transmission of the PDSCH to the UE (the dashed arrow in the bottom of Fig.12). Moreover, the plurality of available HARQ IDs in the TRP is added with this sub-plurality , refernce numeral 3 in Fig.13. Since the UE removes from the buffer, upon reception of said information, data corresponding to sub-TTIs with HARQ IDs from the sub-plurality , then said sub-plurality of HARQ IDs is excluded from the plurality of used HARQ IDs in the UE: , refernce numeral 3 in Fig.13

[0182] Reference numeral 4 in Fig.13 corresponds to reserving a TTI by said subsequent DCI, along with performing the actions similarly to reference numeral 1 in this figure.

[0183] Thereafter, in accordance with the disclosure according to Figs.10-11, in the case of the embodiment with the implicit informing, the timer(s) of the predefined duration is started in the TRP and in the UE. The illustration of Fig.14 corresponds to an unlimiting example of starting the timer associated with transmission of the DCI. Though in Fig.14 the timer is shown as expiring in the next DL / UL-period, this does not impose a limitation onto the present disclosure either, and timers of a different duration may be used - for instance, the predefined timer duration can encompass plural DL / UL-periods.

[0184] As outlined in said disclosure, upon expiration of the timer, HARQ IDs, for which NACKs were sent from the UE and retransmitted data were not received from the TRP within the timer duration, are by default identified in the UE as HARQ IDs not used for actual transmission of the PDSCH in the previously reserved TTI. The HARQ IDs identified in such a way are denoted as the UE as in Fig.14. Since the UE removes from the buffer data corresponding to sub-TTIs with HARQ IDs from the plurality , then said plurality of HARQ IDs is excluded from the plurality of used HARQ IDs in the UE: , reference numeral 4 in Fig.14. Moreover, the plurality of available HARQ IDs in the TRP, upon expiration of the timer, is added with this sub-plurality , reference numeral 4 in Fig.14.

[0185] Reference numeral 3 in Fig.14, like reference numeral 4 in Fig.13, corresponds to reserving a TTI by the subsequent DCI, along with performing the actions similarly to reference numeral 1 in Figs.13, 14.

[0186] An embodiment of the method 1500 of flexibly allocating time domain resources according to the present disclosure is disclosed hereinafter with reference to Fig.15.

[0187] In step 1510, the base station (for example, the TRP 302 in Fig.3) allocates a predetermined number of adjacent OFDM-symbols for transmission of the PDCCH, similarly to step 810.

[0188] In step 1520, the base station allocates a bundle of slots / mini-slots (TTI) comprising a set of adjacent slots / mini-slots (sub-TTIs), where each sub-TTI includes a predetermined number of OFDM-symbols. As stated above, a slot can include 12 or 14 OFDM-symbols, mini-slot can include 2, 4, or 7 OFDM-symbols. The base station assigns, to each sub-TTI in the allocated TTI, its own HARQ ID.

[0189] In step 1530, the base station allocates, within the TTI, a subset of adjacent sub-TTIs for transmission of the PDSCH to the UE (see Fig.10a, 10b, 11).

[0190] In step 1540, the base station reserves the entire TTI (with overbooking) for the transmission of the PDSCH to the UE by transmitting to the UE the PDCCH which carries DCI including at least information enabling the UE to determine HARQ IDs of all the sub-TTIs of the reserved TTI. In accordance with the embodiment, an array of the HARQ IDs of the sub-TTIs of the reserved TTI is sent as said information in the DCI. As discussed above, the DCI includes an indication of the beginning of the TTI and of the end of the TTI, where the indication of the beginning of the TTI is preferably an indication of the starting OFDM-symbol of the TTI, and the indication of its end is an indication of the number of sub-TTIs in the TTI.

[0191] In step 1550, the base station transmits the PDSCH to the UE in said subset of sub-TTIs. The arrangement of code blocks of data transmitted in the PDSCH, as described above with reference to Fig.6 (see also step 860 in Fig.8a), is preferably used.

[0192] In step 1560, the UE places into its buffer received data from all the sub-TTIs of the TTI. Then, with respect to each of the sub-TTIs, the UE performs, from the buffer, decoding of data corresponding to the sub-TTI and sends, to the base station, an acknowledgement by the PUCCH. As outlined above, if the decoding is successful, ACK is sent as the acknowledgement, and said corresponding data is removed from the buffer; and, if the decoding is not successful, NACK is sent as the acknowledgement, and said corresponding data remains in the buffer. It should be emphasized again that decoding of ‘garbage’ data, i.e. data from sub-TTIs not comprised by the subset of sub-TTIs which was allocated within the TTI in step 1530 always completes unsuccessfully in the UE, and, accordingly, NACKs are subsequently sent.

[0193] In step 1570, the base station, upon reception of NACK with respect to data transmitted in some sub-TTI of said subset of sub-TTIs, retransmits said data to the UE. In this case, as discussed above, an error occurred in initial transmission of the data by the PDSCH in the considered sub-TTI, i.e. it was payload but ‘erroneous’ data. The UE in turn receives the retransmitted data and combines it with the ‘erroneous’ data corresponding to said sub-TTI and remaining in the buffer, and performs decoding of such combined data. Consistent identification of respective sub-TTIs in the TRP and in the UE is implemented, of course, by means of HARQ IDs assigned by the base station in step 1520 and signaled thereby to the UE in step 1540.

[0194] In step 1580, the UE is post factum informed about sub-TTIs from the TTI which are not comprised by the subset of sub-TTIs allocated in step 1530, i.e., in other words, about sub-TTIs which were not used in the TTI for the transmission of the PDSCH to the UE.

[0195] In accordance with the disclosure provided above, according to the one embodiment of the present disclosure, said informing can be implemented in the explicit way (see Figs.11-13), which corresponds to substep 1581 in Fig.15. In step 1581, the base station transmits to the UE, within subsequent DCI, HARQ IDs of the sub-TTIs of the subset of sub-TTIs which was allocated in step 1530 for the PDSCH (т.е. HARQ IDs which form the sub-plurality ), or HARQ IDs of sub-TTIs which are not comprised by said subset (i.e. HARQ IDs which form the sub-plurality ). Upon reception of the subsequent DCI, the UE removes from its buffer all data corresponding to the sub-TTIs not comprised by said subset of sub-TTIs, i.e. all data which have turned out to be ‘garbage’.

[0196] According to the other embodiment of the present disclosure, the informing of step 1580 can be implemented in the implicit way (see Fig.14), which corresponds to substep 1582 in Fig.15.

[0197] According to the one implementation of step 1582, upon the transmission of the DCI in step 1540, a timer of a predetermined duration is started in the base station, and, upon reception of said DCI and with account of the time of signal propagation between the base station and the UE, a timer of the predetermined duration is also started in the UE. Upon expiration of the predetermined timer duration, UE by default determines sub-TTIs, for which NACKs were sent from the UE to the base station in step 1570 and for which retransmitted data were not received from the base station within said predetermined duration, as the sub-TTIs not comprised by the subset of sub-TTIs which was allocated in the TTI in step 1530 for the PDSCH. Thereafter, ‘garbage’ data corresponding to the sub-TTIs determined in such a way are removed from the buffer of the UE.

[0198] According to the alternative implementation of substep 1582, an individual timer of a predefined duration is started in the base station upon transmission in each sub-TTI of the reserved TTI, and, upon reception of data in the sub-TTI and with account of the time of signal propagation between the base station and the UE, a timer of said predefined duration is also started in the UE. Upon expiration of the predefined timer duration, the UE by default determines said sub-TTI as a sub-TTI not comprised by the subset of sub-TTIs which was allocated in the TTI in step 1530 for the PDSCH if NACK was transmitted with respect to said sub-TTI from the UE to the base station and retransmitted data was not received from the base station within said predefined duration. Thereafter, ‘garbage’ data corresponding to all sub-TTIs determined in such a way are removed from the buffer of the UE.

[0199] For both considered implementations of substep 1582, the predefined timer duration is set in the base station and signaled, prior to the start of the timer, to the user device preferably by MAC signaling or RRC signaling.

[0200] As disclosed above with reference to Figs.12-14, the base station maintains the plurality of HARQ IDs which are available for being assigned to slots / mini-slots (sub-TTIs) for transmission of new data. After the reserving according to step 1540, the HARQ IDs assigned to the sub-TTIs of the reserved TTI are excluded from the plurality . At the same time, the plurality is added with HARQ IDs for which ACKs sent from the UE in step 1560 have been received in the base station. Finally, after the informing according to step 1580, the plurality is added with HARQ IDs of sub-TTIs which have not been not comprised by said subset of sub-TTIs, i.e. with the sub-plurality of HARQ IDs.

[0201] In accordance with the present disclosure, the UE maintains the plurality of used HARQ IDs for sub-TTIs whose corresponding data are in the buffer. After placing data into the buffer according to step 1560, the plurality is added with HARQ IDs of all the sub-TTIs of the reserved TTI, i.e. with the plurality . HARQ IDs of sub-TTIs whose corresponding data are removed from the buffer of the UE in steps 1560, 1580 are accordingly excluded from the plurality .

[0202] It should be appreciated, though not recited directly, that the method 1500 further comprises (e.g. after step 1520) allocating at least one DMRS subbundle to transmit DMRS signals, similarly to step 830.

[0203] FIG. 16 illustrates a block diagram of a terminal (or a user equipment (UE)), according to embodiments of the present disclosure.

[0204] As shown in FIG. 16, a terminal according to an embodiment may include a transceiver 1610, a memory 1620, and a controller (or a processor) 1630. The transceiver 1610, the memory 1620, and the controller (or the processor) 1630 of the terminal may operate according to a communication method of the terminal described above. However, the components of the terminal are not limited thereto. For example, the terminal may include more or fewer components than those described in Fig. 16. In addition, the controller (or the processor) 1630, the transceiver 1610, and the memory 1620 may be implemented as a single chip. Also, the controller (or the processor) 1630 may include at least one processor.

[0205] The transceiver 1610 collectively refers to a terminal station receiver and a terminal transmitter, and may transmit / receive a signal to / from a base station or another terminal. The signal transmitted or received to or from the terminal may include control information and data. The transceiver 1610 may include a RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and a RF receiver for amplifying low-noise and down-converting a frequency of a received signal. However, this is only an example of the transceiver 1610 and components of the transceiver 1610 are not limited to the RF transmitter and the RF receiver.

[0206] Also, the transceiver 1610 may receive and output, to the controller (or the processor) 1630, a signal through a wireless channel, and transmit a signal output from the controller (or the processor) 1630 through the wireless channel.

[0207] The memory 1620 may store a program and data required for operations of the terminal. Also, the memory 1620 may store control information or data included in a signal obtained by the terminal. The memory 1620 may be a storage medium, such as read-only memory (ROM), random access memory (RAM), a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

[0208] The controller (or the processor) 1630 may control a series of processes such that the terminal operates as described above. For example, the controller (or the processor) 1630 may receive a data signal and / or a control signal, and the controller (or the processor) 1630 may determine a result of receiving the signal transmitted by the base station and / or the other terminal.

[0209] FIG. 17 illustrates a block diagram of a base station, according to embodiments of the present disclosure.

[0210] As shown in FIG. 17, the base station of the present disclosure may include a transceiver 1710, a memory 1720, and a controller (or, a processor) 1730. The transceiver 1710, the memory 1720, and the controller (or the processor) 1730 of the base station may operate according to a communication method of the base station described above. However, the components of the base station are not limited thereto. For example, the base station may include more or fewer components than those described in Fig. 17. In addition, the controller (or the processor) 1730, the transceiver 1710, and the memory 1720 may be implemented as a single chip. Also, the controller (or the processor) 1730 may include at least one processor.

[0211] The transceiver 1710 collectively refers to a base station receiver and a base station transmitter, and may transmit / receive a signal to / from a terminal, another base station, and / or a core network function(s) (or entity(s)). The signal transmitted or received to or from the base station may include control information and data. The transceiver 1710 may include a RF transmitter for up-converting and amplifying a frequency of a transmitted signal, and a RF receiver for amplifying low-noise and down-converting a frequency of a received signal. However, this is only an example of the transceiver 1710 and components of the transceiver 1710 are not limited to the RF transmitter and the RF receiver.

[0212] Also, the transceiver 1710 may receive and output, to the controller (or the processor) 1730, a signal through a wireless channel, and transmit a signal output from the controller (or the processor) 1730 through the wireless channel.

[0213] The memory 1720 may store a program and data required for operations of the base station. Also, the memory 1720 may store control information or data included in a signal obtained by the base station. The memory 1720 may be a storage medium, such as ROM, RAM, a hard disk, a CD-ROM, and a DVD, or a combination of storage media.

[0214] The controller (or the processor) 1730 may control a series of processes such that the base station operates as described above. For example, the controller (or the processor) 1730 may receive a data signal and / or a control signal, and the controller (or the processor) 1730 may determine a result of receiving the signal transmitted by the terminal and / or the core network function.

[0215] The methods according to the embodiments described in the claims or the detailed description of the present disclosure may be implemented in hardware, software, or a combination of hardware and software.

[0216] When the electrical structures and methods are implemented in software, a computer-readable recording medium having one or more programs (software modules) recorded thereon may be provided. The one or more programs recorded on the computer-readable recording medium are configured to be executable by one or more processors in an electronic device. The one or more programs include instructions to execute the methods according to the embodiments described in the claims or the detailed description of the present disclosure.

[0217] Those skilled in the art will understand that the above illustrative embodiments are described herein and are not intended to be limiting. It should be understood that any two or more of the embodiments disclosed herein may be combined in any combination. Furthermore, other embodiments may be utilized and other changes may be made without departing from the spirit and scope of the subject matter presented herein. It will be readily understood that aspects of the invention of the disclosure as generally described herein and shown in the drawings may be arranged, replaced, combined, separated and designed in various different configurations, all of which are contemplated herein.

[0218] Those skilled in the art will understand that the various illustrative logical blocks, modules, circuits, and steps described in this application may be implemented as hardware, software, or a combination of both. To clearly illustrate this interchangeability between hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above in the form of their functional sets. Whether such function sets are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Technicians may implement the described functional sets in different ways for each specific application, but such design decisions should not be interpreted as causing a departure from the scope of this application.

[0219] The various illustrative logic blocks, modules, and circuits described in this application may be implemented or performed by a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic devices, discrete gates or transistor logics, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general purpose processor may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration.

[0220] The steps of the method or algorithm described in this application may be embodied directly in hardware, in a software module executed by a processor, or in a combination thereof. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, register, hard disk, removable disk, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor to enable the processor to read and write information from / to the storage media. In an alternative, the storage medium may be integrated into the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and the storage medium may reside in the user terminal as discrete components.

[0221] In one or more exemplary designs, the functions may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, each function may be stored as one or more pieces of instructions or codes on a computer-readable medium or delivered through it. The computer-readable medium includes both a computer storage medium and a communication medium, the latter including any medium that facilitates the transfer of computer programs from one place to another. The storage medium may be any available medium that can be accessed by a general purpose or special purpose computer.

[0222] The above description is only an exemplary implementation of the present invention, and is not intended to limit the scope of protection of the present invention, which is determined by the appended claims.

[0223] In accordance with the preferred embodiment, the approach to flexible allocation of time resources according to the present disclosure, as described above, is applicable to broadband transmission, when simultaneous transmission of multiple spatial MIMO layers of the PDSCH is supported. At the same time, this preferred embodiment does not impose a limitation, and said approach equally applies to implementations with one MIMO layer. Of course, the approach according to the present disclosure is fully applicable to 5G NR systems as well.

[0224] Moreover, though the embodiments disclosed above are illustrated in the context of TDD systems, it should be emphasized that the approach according to the present disclosure is also applicable to frequency division duplex (FDD) systems in which different frequencies are used for downlink transmission and uplink transmission at every time instant.

[0225] As follows from the aforesaid, the present disclosure provides less buffering demands in the base station when scheduling downlink transmission with aggregation of time domain resources, and simpler preparation of DCI (for example, the TRP in scenarios with not full load of the network can generate DCI without precise knowledge of an amount of resources in the time domain), as well as reduced latency by enabling to perform downlink transmission of new data with using time resources not involved for the scheduled downlink data transmission, before the aggregated TTI ends.

[0226] It should be also appreciated that the illustrated exemplary embodiments merely refer to preferable, but not the only possible implementations of the present disclosure. More particularly, the scope of the present disclosure is defined by the claims presented below and equivalents thereof.

Claims

1.A method of allocating resources in a time domain in a wireless communication system, the method comprising:in a base station (TRP),allocating a predetermined number of adjacent OFDM-symbols for transmission of a physical downlink control channel (PDCCH),allocating a bundle of time intervals, said bundle comprising a set of adjacent time intervals, wherein each time interval includes a predetermined number of OFDM-symbols, wherein an identifier is assigned to each time interval in the bundle of time intervals,allocating, within the bundle of time intervals, a subset of adjacent time intervals for transmission of a physical downlink shared channel (PDSCH) to a user device (UE),reserving the bundle of time intervals for the transmission of the PDSCH to the user device by transmitting to the UE the PDCCH which carries downlink control information (DCI) including at least information enabling to determine identifiers of all the time intervals of the bundle of time intervals, andtransmitting the PDSCH to the UE in said subset of time intervals; andinforming the UE about time intervals of the bundle of time intervals which are not comprised by the subset of time intervals.2.The method according to claim 1, further comprising, in the user device:placing, into a buffer, received data from the time intervals of the bundle of time intervals;with respect to each of the time intervals of the bundle of time intervals, decoding, from the buffer, data corresponding to the time interval, and sending to the base station an acknowledgement in a physical uplink control channel (PUCCH), whereinif the decoding is successful: a positive acknowledgement (ACK) is sent as said acknowledgement, and the corresponding data is removed from the buffer,if the decoding is unsuccessful: a negative acknowledgement (NACK) is sent as said acknowledgement, and the corresponding data is left in the buffer,wherein decoding data from the time intervals of the bundle of time intervals which are not comprised by said subset of time intervals is always unsuccessful.3.The method according to claim 2, further comprising:in the base station, upon reception of a NACK with respect to data transmitted in a time interval of the subset of time intervals, retransmitting said data to the user device; andin the user device, combining the retransmitted data received in the user device with data from the buffer that corresponds to said time interval, and decoding the combined data.4.The method according to claim 1, wherein the informing comprises, in the base station: transmitting, within subsequent DCI, identifiers of the time intervals of said subset of time intervals or identifiers of the time intervals of the bundle of time intervals which are not comprised by the subset of time intervals.5.The method according to claim 2, wherein the informing comprises, in the base station: transmitting, within subsequent DCI, identifiers of the time intervals of said subset of time intervals or identifiers of the time intervals of the bundle of time intervals which are not comprised by the subset of time intervals.6.The method according to claim 5, further comprising, in the user device: upon reception of the subsequent DCI, removing, from the buffer, data corresponding to the time intervals not comprised by the subset of time intervals.7.The method according to claim 3, further comprising: starting a timer of a predefined duration in the base station after the transmission of the DCI in the PDCCH, and starting a timer of the predefined duration in the user device upon reception of the DCI, with account of time of signal propagation between the base station and the user device,wherein the method comprises, in the user device, upon expiration of the predefined duration of the timer:determining, as the time intervals not comprised by the subset of time intervals, time intervals with respect to which NACKs were sent from the user device to the base station and for which retransmitted data were not received from the base station within said predefined duration, thereby implementing said informing; andremoving, from the buffer, data corresponding to the determined time intervals.8.The method according to claim 3, further comprising: starting an individual timer of a predefined duration in the base station upon completion of transmission in each time interval of the bundle of time intervals, and starting a timer of the predefined duration in the user device upon reception of data in said time interval, with account of time of signal propagation between the base station and the user device,wherein the method comprises, in the user device:upon expiration of the predefined duration of the timer, determining said time interval as a time interval of the bundle time intervals which is not comprised by the subset of time intervals if, for said time interval, a NACK was sent from the user device to the base station and retransmitted data was not received from the base station within said predefined duration, thereby implementing said informing; andremoving, from the buffer, data corresponding to the determined time intervals.9.The method according to claim 2, wherein a plurality of available identifiers is maintained in the base station which are available for being assigned to time intervals, whereinupon said reserving, the identifiers assigned to the time intervals of the bundle of time intervals are excluded from the plurality of available identifiers;the plurality of available identifiers is added with identifiers with respect to which ACKs have been received in the base station from the user device;upon said informing, the plurality of available identifiers is added with the identifiers of the time intervals which have not been comprised by said subset of time intervals.10.The method according to claim 2, wherein a plurality of used identifiers is maintained in the user device for time intervals whose data have been placed into the buffer, whereinupon said placing data into the buffer, the plurality of used identifiers is added with the identifiers of the time intervals of the bundle of time intervals;identifiers of time intervals whose corresponding data are removed from the buffer are excluded from the plurality of used identifiers.11.The method according to claim 1, wherein the DCI includes an indication of a beginning of the bundle of time intervals and of an end of the bundle of time intervals.12.The method according to claim 11, wherein the indication of the beginning of the bundle of time intervals is an indication of a start OFDM-symbol of the bundle of time intervals, and the indication of the end of the bundle of time intervals is an indication of a number of time intervals in the bundle of time intervals.13.The method according to clam 1, wherein a time interval isa slot comprising 12 or 14 OFDM-symbols, ora mini-slot comprising 2, 4, or 7 OFDM-symbols.14.The method according to claim 1, wherein the identifier is a HARQ ID.15.A base station (TRP) in a wireless communication system, the base station comprising, at least:a transceiver; anda controller coupled with the transceiver and configured to:allocate a predetermined number of adjacent OFDM-symbols for transmission of a physical downlink control channel (PDCCH),allocate a bundle of time intervals, said bundle comprising a set of adjacent time intervals, wherein each time interval includes a predetermined number of OFDM-symbols, wherein an identifier is assigned to each time interval in the bundle of time intervals,allocate, within the bundle of time intervals, a subset of adjacent time intervals for transmission of a physical downlink shared channel (PDSCH) to a user device (UE),reserve the bundle of time intervals for the transmission of the PDSCH to the user device by transmitting to the UE the PDCCH which carries downlink control information (DCI) including at least information enabling to determine identifiers of all the time intervals of the bundle of time intervals, andtransmit the PDSCH to the UE in said subset of time intervals, andinform the UE about time intervals of the bundle of time intervals which are not comprised by the subset of time intervals.

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