WO2023123345A1

WO2023123345A1 - Methods and apparatuses for channel estimation based on dmrs

Info

Publication number: WO2023123345A1
Application number: PCT/CN2021/143660
Authority: WO
Inventors: Lingling Xiao; Bingchao LIU; Chenxi Zhu; Wei Ling; Yi Zhang
Original assignee: Lenovo (Beijing) Limited
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2023-07-06

Abstract

Embodiments of the present disclosure relate to methods and apparatuses for channel estimation based on demodulation reference signal (DMRS). According to an embodiment of the present disclosure, a user equipment can include: a receiver that receives downlink control information (DCI) for scheduling a plurality of physical downlink shared channel (PDSCH) transmissions; a processor that is coupled to the receiver and determines one or more groups of PDSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PDSCH transmissions of the plurality of PDSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots; and a transmitter coupled to the processor; wherein the receiver further receives one or more DMRS symbols in each group of the one or more groups, and wherein the processor further decodes each of the one or more PDSCH transmissions included in each group based on all of the one or more DMRS symbols in the group in response to an indicator.

Description

METHODS AND APPARATUSES FOR CHANNEL ESTIMATION BASED ON DMRS

TECHNICAL FIELD

Embodiments of the present application generally relate to wireless communication technology, and in particular to methods and apparatuses for channel estimation based on demodulation reference signal (DMRS) .

BACKGROUND

DMRS is an important reference signal in long-term evolution (LTE) and new radio (NR) system, which can be used for uplink channel estimation or downlink channel estimation, thereby facilitating decoding physical uplink shared channel (PUSCH) transmissions or physical downlink shared channel (PDSCH) transmissions. In Rel-15 or Rel-16, once DMRS is configured in a bandwidth part (BWP) , its density and location within a slot or a sub-slot is determined by a radio resource control (RRC) configuration.

Normally, a higher density of DMRS can achieve a better performance of channel estimation but the corresponding DMRS overhead will be higher. Then, how to reduce the DMRS overhead while guaranteeing the performance of channel estimation needs to be addressed.

SUMMARY OF THE APPLICATION

Some embodiments of the present application provide a technical solution for channel estimation based on DMRS.

According to some embodiments of the present application, a method performed by a user equipment (UE) may include: receiving downlink control information (DCI) for scheduling a plurality of PDSCH transmissions; determining one or more groups of PDSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PDSCH transmissions of the plurality of PDSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots; receiving one or more DMRS symbols in each group of the one or more groups; and decoding each of the one or more PDSCH transmissions included in each group based on all of the one or more DMRS symbols in the group in response to an indicator.

In some embodiments of the present application, the indicator is configured by a radio resource control (RRC) signaling or indicated by the DCI based on the UE's capability.

In some embodiments of the present application, the group duration is a fixed value or a pre-defined value, and the group duration is an integer multiple of a time duration of a slot or sub-slot with a reference subcarrier spacing.

In some embodiments of the present application, the group duration is configured via an RRC signaling from a based station (BS) , and the group duration is independent of a subcarrier spacing of the plurality of PDSCH transmissions.

In some embodiments of the present application, the group duration is configured via an RRC signaling from a BS, and the group duration is associated with a subcarrier spacing of the plurality of PDSCH transmissions.

In some embodiments of the present application, the group duration is a number of slots or sub-slots in each group, an integer multiple of a time duration of one slot or one sub-slot of the plurality of PDSCH transmissions, or a time duration of a slot or sub-slot with a reference subcarrier spacing.

In some embodiments of the present application, the method may further include: receiving more than one candidate group duration configured via an RRC signaling, and a medium access control (MAC) control element (CE) including a field indicating one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, the method may further include receiving more than one candidate group duration configured via an RRC signaling, and the DCI includes a field indicating one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, the method may further include: receiving more than one candidate proportion configured via an RRC signaling, and a MAC CE including a field indicating one proportion of the more than one candidate proportion; and determining location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the method may further include: receiving more than one proportion configured via an RRC signaling, wherein the DCI includes a field indicating one proportion of the more than one candidate proportion; and determining location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the method may further include: receiving a proportion configured via an RRC signaling, and determining location (s) of the one or more DMRS symbols in each group based on the proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the method may further include: determining location (s) of the one or more DMRS symbols in each group based on a number of PDSCH transmissions in the group and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the method may further include: receiving location (s) of the one or more DMRS symbols in each group or location (s) of at least one DMRS symbol in each PDSCH transmission in each group configured via an RRC signaling.

According to some embodiments of the present application, a method performed by a BS may include: transmitting DCI for scheduling a plurality of PDSCH transmissions; determining one or more groups of PDSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PDSCH transmissions of the plurality of PDSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots; transmitting one or more DMRS symbols in each group of the one or more groups, and transmitting an indicator based on a capability of a UE to indicate the UE to decode each of the one or more PDSCH transmissions in each group based on all of the one or more DMRS symbols in the group.

In some embodiments of the present application, the indicator is transmitted via an RRC signaling or transmitted in the DCI.

In some embodiments of the present application, the method may further include transmitting the group duration via an RRC signaling to the UE, and the group duration is independent of a subcarrier spacing of the plurality of PDSCH transmissions.

In some embodiments of the present application, the method may further include transmitting the group duration via an RRC signaling to the UE, and the group duration is associated with a subcarrier spacing of the plurality of PDSCH transmissions.

In some embodiments of the present application, the group duration is a number of slots or sub-slots in each group, an integer multiple of a time duration of one slot or one sub-slot of the plurality of PDSCH transmissions, or a time duration of a slot or a sub-slot with a reference subcarrier spacing.

In some embodiments of the present application, the method may further include transmitting: more than one candidate group duration via an RRC signaling; and a MAC CE including a field indicating one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, the method may further include transmitting more than one candidate group duration via an RRC signaling, and the DCI includes a field indicating one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, the method may further include: transmitting more than one candidate proportion via an RRC signaling, and a MAC CE including a field indicating one proportion of the more than one candidate proportion; and determining location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the method may further include: transmitting more than one proportions via an RRC signaling, wherein the DCI includes a field indicating one proportion of the more than one candidate proportion; and determining location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the method may further include: transmitting a proportion via an RRC signaling, and determining location (s) of the one or more DMRS symbols in each group based on the proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the method may further include: transmitting location (s) of the one or more DMRS symbols in each group or location (s) of at least one DMRS symbol in each PDSCH transmission in each group via an RRC signaling.

According to some other embodiments of the present application, a method performed by a UE may include: receiving DCI or a configured grant for scheduling a plurality of PUSCH transmissions; determining one or more groups of PUSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PUSCH transmissions of the plurality of PUSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots; and transmitting one or more DMRS symbols in each group of the one or more groups.

In some embodiments of the present application, the group duration is configured via an RRC signaling from a BS, and the group duration is independent of a subcarrier spacing of the plurality of PUSCH transmissions.

In some embodiments of the present application, the group duration is configured via an RRC signaling from a BS, and the group duration is associated with a subcarrier spacing of the plurality of PUSCH transmissions.

In some embodiments of the present application, the group duration is a number of slots or sub-slots in each group, an integer multiple of a time duration of one slot or one sub-slot of the plurality of PUSCH transmissions, or a time duration of a slot or a sub-slot with a reference subcarrier spacing.

In some embodiments of the present application, the method may further include: receiving more than one candidate group duration configured via an RRC signaling, and a MAC CE including a field indicating one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, the method may further include receiving more than one candidate group duration configured via an RRC signaling, and the DCI or configured grant includes a field indicating one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, the method may further include: receiving more than one proportion configured via an RRC signaling, wherein the DCI or configured grant includes a field indicating one proportion of the more than one candidate proportion; and determining location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the method may further include: determines location (s) of the one or more DMRS symbols in each group based on a number of PUSCH transmissions in the group and location (s) of DMRS symbol (s) based on a DMRS position table.

In some embodiments of the present application, the method may further include: receiving location (s) of the one or more DMRS symbols in each group or location (s) of at least one DMRS symbol in each PUSCH transmission in each group configured via an RRC signaling.

According to some embodiments of the present application, a method performed by a BS may include: transmitting, to a UE, DCI or a configured grant for scheduling a plurality of PUSCH transmissions; determining one or more groups of PUSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PUSCH transmissions of the plurality of PUSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots; and receiving one or more DMRS symbols in each group of the one or more groups.

In some embodiments of the present application, the method may further include transmitting the group duration via an RRC signaling to the UE, and the group duration is independent of a subcarrier spacing of the plurality of PUSCH transmissions.

In some embodiments of the present application, the method may further include transmitting the group duration via an RRC signaling to the UE, and the group duration is associated with a subcarrier spacing of the plurality of PUSCH transmissions.

In some embodiments of the present application, the method may further include transmitting more than one candidate group duration via an RRC signaling, and the DCI or configured grant includes a field indicating one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, the method may further include transmitting more than one candidate proportion via an RRC signaling, and a MAC CE including a field indicating one proportion of the more than one candidate proportion; and determining location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the method may further include: transmitting more than one proportion via an RRC signaling, wherein the DCI or configured grant includes a field indicating one proportion of the more than one candidate proportion; and determining location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the method may further include: determining location (s) of the one or more DMRS symbols in each group based on a number of PUSCH transmissions in the group and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the method may further include: transmitting location (s) of the one or more DMRS symbols in each group or location (s) of at least one DMRS symbol in each PUSCH transmission in each group via an RRC signaling.

According to some embodiments of the present application, a UE may include: a receiver that receives DCI for scheduling a plurality of PDSCH transmissions; a processor that is coupled to the receiver and determines one or more groups of PDSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PDSCH transmissions of the plurality of PDSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots; and a transmitter coupled to the processor; wherein the receiver further receives one or more DMRS symbols in each group of the one or more groups, and wherein the processor further decodes each of the one or more PDSCH transmissions included in each group based on all of the one or more DMRS symbols in the group in response to an indicator.

According to some embodiments of the present application, a BS may include: a transmitter that transmits DCI for scheduling a plurality of PDSCH transmissions; a processor that is coupled to the transmitter and determines one or more groups of PDSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PDSCH transmissions of the plurality of PDSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots; and a receiver coupled to the processor; wherein the transmitter further transmits one or more DMRS symbols in each group of the one or more groups, and wherein the transmitter transmits an indicator based on a capability of a UE to indicate the UE to decode each of the one or more PDSCH transmissions in each group based on all of the one or more DMRS symbols in the group.

According to some embodiments of the present application, a UE may include: a receiver that receives DCI or a configured grant for scheduling a plurality of PUSCH transmissions; a processor that is coupled to the receiver and determines one or more groups of PUSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PUSCH transmissions of the plurality of PUSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots; and a transmitter that is coupled to the processor and transmits one or more DMRS symbols in each group of the one or more groups.

According to some embodiments of the present application, a BS may include: a transmitter that transmits, to a UE, DCI or a configured grant for scheduling a plurality of PUSCH transmissions; and a processor that is coupled to the transmitter and determines one or more groups of PUSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PUSCH transmissions of the plurality of PUSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots; and a receiver that is coupled to the processor and receives one or more DMRS symbols in each group of the one or more groups.

Embodiments of the present application provide a technical solution for channel estimation based on DMRS, which can reduce the DMRS overhead while guaranteeing the performance of channel estimation.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which advantages and features of the application can be obtained, a description of the application is rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. These drawings depict only example embodiments of the application and are not therefore to be considered limiting of its scope.

FIG. 1 is a schematic diagram illustrating an exemplary wireless communication system according to some embodiments of the present application;

FIG. 2 illustrates exemplary PDSCH transmission groups according to some embodiments of the present application;

FIG. 3 illustrates a flow chart of an exemplary method for channel estimation based on DMRS according to some embodiments of the present application;

FIG. 4 illustrates an exemplary indicator configured by an RRC signaling according to some embodiments of the present application;

FIG. 5 illustrates exemplary DMRS symbol patterns in a group of PDSCH transmissions according to some embodiments of the present application;

FIG. 6 illustrates exemplary DMRS symbol patterns in a group of PDSCH transmissions according to some other embodiments of the present application;

FIG. 7 illustrates exemplary DMRS symbol patterns in a group of PDSCH transmissions according to some other embodiments of the present application;

FIG. 8 illustrates a flow chart of another exemplary method for channel estimation based on DMRS according to some other embodiments of the present application; and

FIG. 9 illustrates a simplified block diagram of an exemplary apparatus for channel estimation based on DMRS according to some embodiments of the present application.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of the preferred embodiments of the present application and is not intended to represent the only form in which the present application may be practiced. It should be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present application.

Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under specific network architecture and new service scenarios, such as the 3rd generation partnership project (3GPP) 5G (NR) , 3GPP long-term evolution (LTE) , and so on. It is contemplated that along with the developments of network architectures and new service scenarios, all embodiments in the present application are also applicable to similar technical problems; and moreover, the terminologies recited in the present application may change, which should not affect the principle of the present application.

A wireless communication system generally includes one or more base stations (BSs) and one or more UEs. Furthermore, a BS may be configured with one TRP (or panel) or more TRPs (or panels) . A TRP can act like a small BS. The TRPs can communicate with each other by a backhaul link. Such backhaul link may be an ideal backhaul link or a non-ideal backhaul link. Latency of the ideal backhaul link may be deemed as zero, and latency of the non-ideal backhaul link may be tens of milliseconds and much larger, e.g. on the order of tens of milliseconds, than that of the ideal backhaul link.

In a wireless communication system, one single TRP can be used to serve one or more UEs under control of a BS. In different scenarios, TRP may be called in different terms. Persons skilled in the art should understand that as the 3GPP and the communication technology develop, the terminologies recited in the specification may change, which should not affect the scope of the present application. It should be understood that the TRP (s) (or panel (s) ) configured for the BS may be transparent to a UE.

FIG. 1 is a schematic diagram illustrating an exemplary wireless communication system 100 according to some embodiments of the present application.

Referring to FIG. 1, the wireless communication system 100 can include a BS 101, TRPs 103 (e.g., TRP 103a and TRP 103b) , and UEs 105 (e.g., UE 105a, UE 105b, and UE 105c) . Although only one BS 101, two TRPs 103 and three UEs 105 are shown for simplicity, it should be noted that the wireless communication system 100 may include more or less communication device (s) , apparatus, or node (s) in accordance with some other embodiments of the present application.

In some embodiments of the present application, the BS 101 may be referred to as an access point, an access terminal, a base, a base unit, a macro cell, a Node-B, an evolved Node B (eNB) , a gNB, an ng-eNB, a Home Node-B, a relay node, or a device, or described using other terminology used in the art. The UEs 105 (for example, the UE 105a, the UE 105b, and the UE 105c) may include, for example, but is not limited to, a computing device, a wearable device, a mobile device, an internet of things (IoT) device, a vehicle, etc.

The TRPs 103, for example, the TRP 103a and the TRP 103b, can communicate with the BS 101 via, for example, a backhaul link. Each of TRPs 103 can serve some or all of the UEs 105. As shown in FIG. 1, the TRP 103a can serve some mobile stations (which include the UE 105a, the UE 105b, and the UE 105c) within a serving area or region (e.g., a cell or a cell sector) . The TRP 103b can serve some mobile stations (which include the UE 105a, the UE 105b, and the UE 105c) within a serving area or region (e.g., a cell or a cell sector) . In some other embodiments, the TRP 103a and the TRP 103b may serve different UEs. The TRP 103a and the TRP 103b can communicate with each other via, for example, a backhaul link.

DMRS can be used for uplink channel estimation or downlink channel estimation, thereby facilitating decoding PUSCH transmissions or PDSCH transmissions. Normally, a higher density of DMRS can achieve a better performance of channel estimation but the corresponding DMRS overhead will be higher. In Rel-15 or Rel-16, once DMRS is configured in a BWP, its density and location within a slot or a sub-slot is determined by an RRC configuration.

In NR, a single DCI scheduling multiple PDSCH (or PUSCH) transmissions in multiple slots or sub-slots is supported, wherein each PDSCH (or PUSCH) transmission is transmitted in a slot or sub-slot. In such cases, the DMRS configuration for different PDSCH (or PUSCH) transmissions is the same. In addition, since the multiple PDSCH (or PUSCH) transmissions are scheduled by one DCI, the antenna port (s) and the quasi co-located (QCL) assumption of different PDSCH (or PUSCH) transmissions are the same, which means that the channel experienced by different PDSCH (or PUSCH) transmissions can be assumed to be the same. The symbols occupied by the DMRS for PDSCH (or PUSCH) transmission may be reduced such that the symbols not used for DMRS may be used for PDSCH (or PUSCH) transmission or for other purposes. In such cases, how to reduce the DMRS overhead while guaranteeing the performance of channel estimation needs to be addressed.

In NR, a single DCI scheduling PDSCH (or PUSCH) repetitions in multiple slots or sub-slots is also supported, wherein the PDSCH (or PUSCH) repetitions may be received from (or transmitted to) different TRPs. For multiple PDSCH (or PUSCH) repetitions from (or to) a same TRP, the antenna port (s) and the QCL assumption of the multiple PDSCH (or PUSCH) repetitions are the same, which means that the channel experienced by the different PDSCH (or PUSCH) repetitions from (or to) a same TRP are the same. The symbols occupied by the DMRS may be reduced such that the symbols not used for DMRS may be used for PDSCH (or PUSCH) transmission or for other purposes. In such cases, how to reduce the DMRS overhead while guaranteeing the performance of channel estimation needs to be addressed.

Given the above, embodiments of the present application aim to provide solutions for channel estimation based on DMRS. Specifically, embodiments of the present application provide several methods for channel estimation based on DMRS in a scenario where a plurality of PDSCH (or PUSCH) transmissions or a plurality of PDSCH (or PUSCH) repetitions are scheduled by a single DCI. Hereinafter, a PDSCH transmission and a PDSCH repetition can be collectively referred to as "a PDSCH transmission, " and a PUSCH transmission and a PUSCH repetition can be collectively referred to as "a PUSCH transmission. " The methods provided by embodiments of the present application can reduce the DMRS overhead while guaranteeing the performance of channel estimation. More details on embodiments of the present application will be described in the following text in combination with the appended drawings.

In the embodiments of the present application, a concept of a group of PDSCH transmissions or a group of PUSCH transmissions (also referred to as a PDSCH transmission group or a PUSCH transmission group) is introduced. In a group of PDSCH (or PUSCH) transmissions, the different PDSCH (or PUSCH) transmissions are expected to experience a same channel between a BS and a UE. For example, the group of PDSCH (or PUSCH) transmissions may include multiple PDSCH (or PUSCH) transmissions in multiple consecutive slots or sub-slots scheduled by a single DCI, or the group of PDSCH (or PUSCH) transmissions may include multiple PDSCH (or PUSCH) repetitions in multiple consecutive slots or sub-slots which are scheduled by a single DCI and received from (or transmitted to) the same TRP. In the group of PDSCH (or PUSCH) transmissions, the UE (or the BS) may estimate the channel based on all the DMRS symbols within the group jointly and then interpolate the channel matrix on symbols of the PDSCH (or PUSCH) transmissions within the group to achieve a higher channel estimation performance.

FIG. 2 illustrates exemplary PDSCH transmission groups according to some embodiments of the present application.

Referring to FIG. 2, it is assumed that: the PDSCH transmissions are type-A PDSCH transmissions as specified in 3GPP standard documents, the RRC signaling configures 4 DMRS symbols (including one front-loaded DMRS symbol and three additional DMRS symbols) in a slot (e.g., including 14 symbols numbered as 0 to 13) ) for a UE and the location of the front-loaded DMRS is symbol 2. Then, according to the methods in Rel-15 and Rel-16, the locations of the four DMRS symbols in a slot are symbol 2, symbol 5, symbol 8 and symbol 11 determined based on a table indicating PDSCH DMRS positions (also referred to as a DMRS position table) (e.g., Table 7.4.1.1.2-3 as specified in TS 38.211) .

In addition, it is assumed that a group of PDSCH transmissions has a group duration of 0.5 ms in the example illustrated in FIG. 2.

Then, for PDSCH transmission with subcarrier spacing (SCS) of 30 KHz (i.e., the duration of a slot is 0.5ms) , a group of PDSCH transmissions includes one PDSCH transmission (e.g., PDSCH transmission #1) in one slot (e.g., slot n) and there are four DMRS symbols within the group.

For PDSCH transmission with subcarrier spacing of 60 KHz (i.e., the duration of a slot is 0.25ms) , a group of PDSCH transmissions includes two PDSCH transmissions (e.g., PDSCH transmission #1 and PDSCH transmission #2) respectively in two consecutive slots (e.g., slot n and slot n+1) and there may be eight DMRS symbols in the group under the same configuration (i.e., 4 DMRS symbols in a slot) .

However, according to our observations, for the PDSCH transmissions in 0.5 ms, four DMRS symbols are enough to guarantee the performance of channel estimation. Then, for PDSCH transmission with subcarrier spacing of 60 KHz, only a half number of DMRS symbols are needed for channel estimation in 0.5 ms. For example, only symbol 2 and symbol 8 for each PDSCH transmission in the group are used for channel estimation and symbol 5 and symbol 11 for each PDSCH transmission in the group can be used for PDSCH data transmission. Then, for PDSCH transmission with subcarrier spacing of 60 KHz, there are also four DMRS symbols in the group as shown in FIG. 2. The performance of channel estimation can be guaranteed by jointly using the four DMRS symbols for each of the two PDSCH transmissions in the group. The same is applicable to PUSCH transmissions.

Accordingly, by introducing a group of PDSCH (or PUSCH) transmissions, the DMRS density for each PDSCH (or PUSCH) transmission can be reduced to save some overhead. At the same time, channel estimation can also be guaranteed because the channel estimation is based on all DMRS symbols in the group jointly. However, how to determine a group of PDSCH (or PUSCH) transmissions by the BS and the UE and how to determine DMRS symbols for each PDSCH (or PUSCH) transmission in the group by the BS and the UE need to be resolved.

Accordingly, the following embodiments of the present application provide methods regarding how to determine a group of PDSCH (or PUSCH) transmissions by the BS and the UE, and how to determine DMRS symbols (i.e., the locations of the DMRS symbols in a slot or in a group) for each PDSCH (or PUSCH) transmission in the group by the BS and the UE.

FIG. 3 illustrates a flow chart of an exemplary method for channel estimation based on DMRS according to some embodiments of the present application. Although the method is illustrated in a system level by a UE and a BS (e.g., UE 105 and BS 101 as illustrated in FIG. 1) , persons skilled in the art can understand that the method implemented in the UE and that implemented in the BS can be separately implemented and incorporated by other apparatus with the like functions.

As shown in FIG. 3, in step 301, the BS may transmit DCI for scheduling a plurality of PDSCH transmissions. In some embodiments of the present application, the plurality of PDSCH transmissions may be a plurality of PDSCH repetitions.

In some embodiments of the present application, the plurality of PDSCH transmissions may be in a plurality of consecutive slots (or in a plurality of consecutive sub-slots) , wherein each PDSCH transmission is transmitted in a slot (or a sub-slot) .

In some other embodiments of the present application, not all of the plurality of PDSCH transmissions are transmitted in consecutive slots (or in consecutive sub-slots) . That is, one or more of the plurality of PDSCH transmissions may be in one or more non-consecutive slots (or in one or more non-consecutive sub-slots) , wherein each PDSCH transmission is transmitted in a slot (or in a sub-slot) .

Consequently, in step 302, the UE may receive the DCI scheduling the plurality of PDSCH transmissions.

In some embodiments, a UE which estimates a channel matrix jointly based on a group of DMRS symbols for a group of PDSCH transmissions as stated above may require a higher capability because it needs to buffer multiple PDSCH transmissions in multiple slots or sub-slots. In such embodiments, the UE may report its capability to the BS. After receiving the UE's capability, the BS may transmit an indicator based on the UE's capability to the UE. The indicator may indicate whether the UE can perform joint channel estimation for each group of PDSCH transmissions based on all DMRS symbols in the group. In other words, the indicator may indicate whether the UE can decode each PDSCH transmission included in each group based on all DMRS symbols in the group.

In some embodiments of the present application, the indicator may be configured by an RRC signaling.

In an embodiment of the present application, the RRC signaling may include at least one of: one or more candidate group durations; or one or more candidate DMRS patterns. Each candidate DMRS pattern may include at least one of: one or more candidate proportions; or location (s) of DMRS symbol (s) in each group or location (s) of at least one DMRS symbol in each PDSCH transmission in each group. Each candidate proportion may represent a candidate ratio of the actual number of DMRS symbols in a group to the total number of DMRS symbols, wherein the total number of DMRS symbols is determined by the number of DMRS symbols in each slot or each sub-slot in the group multiplying the number of PDSCH transmissions in the group, and wherein the number of DMRS symbols in each slot or each sub-slot is determined as in Rel-15 or Rel-16, e.g., determined based on a DMRS position table (e.g., Table 7.4.1.1.2-3 and Table 7.4.1.1.2-4 as specified in TS 38.211) as specified in 3GPP standard documents. Then, the above information included in the RRC signaling may be used as the indicator to indicate whether the UE can perform joint channel estimation for each group of PDSCH transmissions based on all DMRS symbols in the group. For example, in the case that the RRC signaling includes at least one of the above information, it may indicate the UE to decode each PDSCH transmission included in each group based on all the DMRS symbols in the group. In the case that the RRC signaling does not include any of the above information, it may indicate that the UE cannot decode each PDSCH transmission included in each group based on all the DMRS symbols in the group.

For example, FIG. 4 illustrates an exemplary indicator configured by an RRC signaling according to some embodiments of the present application. Referring to FIG. 4, the RRC signaling may include a PDSCH configuration information element (IE) (e.g., PDSCH-Config as specified in 3GPP standard documents) . The configuration for PDSCH may include a parameter (e.g., "DLGroup" ) which is used to configure the PDSCH transmission group. A configuration for a PDSCH transmission group may include and not be limited to a duration of the PDSCH transmission group and a DMRS pattern in the PDSCH transmission group. The parameter "DLGroup" may be used as the indicator to indicate whether the UE can perform joint channel estimation for each group of PDSCH transmissions based on all DMRS symbols in the group. That is, in the case that "PDSCH-Config" includes the "DLGroup, " it may indicate the UE to decode each PDSCH transmission included in each group based on all the DMRS symbols in the group. In the case that "PDSCH-Config" does not include the "DLGroup, " it may indicate the UE not to decode each PDSCH transmission included in each group based on all the DMRS symbols in the group.

In the example of FIG. 4, the parameter "DLGroup" may include a parameter "Duration" and a parameter "DMRSPattern. " The parameter "Duration" may configure the duration of a PDSCH transmission group. In this example, "Duration" may refer to the number of consecutive PDSCH transmissions in a PDSCH transmission group. The parameter "DMRSPattern" may configure the DMRS pattern in a PDSCH transmission group, which may determine the locations of DMRS symbols in the PDSCH transmission group. In this example, the value of this field indicates the ratio of the actual number of DMRS symbols in a group to the total number of DMRS symbols, wherein the total number of DMRS symbols is determined by the number of DMRS symbols in each slot or each sub-slot in the group multiplying the number of PDSCH transmissions in the group, and wherein the number of DMRS symbols in each slot or each sub-slot is determined as in Rel-15 or Rel-16, e.g., determined based on a DMRS position table (e.g., Table 7.4.1.1.2-3 and Table 7.4.1.1.2-4 as specified in TS 38.211) as specified in 3GPP standard documents.

In addition to the above parameters, the parameter "PDSCH-Config" may include other parameters as specified in 3GPP standard documents.

The example in FIG. 4 uses the parameter "DLGroup" as the indicator. However, in some other embodiments, the indicator indicating whether the UE can perform joint channel estimation for each group of PDSCH transmissions based on all DMRS symbols in the group may be other parameters included in an RRC signaling. For example, a new parameter with a value of "disabled" or "enabled" may be added to an RRC signaling and used as an indicator to indicate whether the UE can perform joint channel estimation for each group of PDSCH transmissions based on all DMRS symbols in the group.

In some other embodiments of the present application, the indicator may be indicated by the DCI (in other words, included in the DCI) scheduling the plurality of PDSCH transmissions. In an embodiment of the present application, the indicator may be a 1-bit indication in the DCI. For example, 1-bit indication with a value of "1" may indicate that the joint channel estimation for a group of PDSCH transmissions is enabled, while 1-bit indication with a value of "0" may indicate that the joint channel estimation for a group of PDSCH transmissions is disabled.

Referring back to FIG. 3, it is assumed that the UE has the capability to perform joint channel estimation for a group of PDSCH transmissions. Therefore, after receiving the UE's capability, in step 303, the BS may transmit an indicator based on the UE's capability. The indicator may indicate the UE to decode each PDSCH transmission included in each group based on all DMRS symbols in the group. In the case that the indicator is received via the RRC signaling, step 303 may occur before or after step 301. In the case that the indicator is indicated by the DCI, step 303 may occur concurrently with step 301.

Consequently, in step 304, the UE may receive the indicator via the RRC signaling or receive the indicator in the DCI. The indicator may indicate the UE to decode each PDSCH transmission included in each group based on all DMRS symbols in the group. In the case that the indicator is received via the RRC signaling, step 304 may occur before or after step 302. In the case that the indicator is received in the DCI, step 304 may occur concurrently with step 302.

In step 305, the BS may determine one or more groups of PDSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PDSCH transmissions of the plurality of PDSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots, and each PDSCH transmission is transmitted in a slot or in a sub-slot. Step 305 may occur before, concurrently or after Step 301. Similarly, in step 306, the UE may determine one or more groups of PDSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PDSCH transmissions of the plurality of PDSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots, and each PDSCH transmission is transmitted in a slot or in a sub-slot.

The BS and the UE may use the same group duration to determine the one or more groups of PDSCH transmissions.

According to some embodiments of the present application, the group duration is a fixed value or a pre-defined value.

In some embodiments of the present application, the fixed or pre-defined group duration is an integer multiple of a time duration of a slot or sub-slot with a reference subcarrier spacing. For example, in the case that the PDSCH transmission is transmitted in a slot, the group duration is an integer multiple of a time duration of a slot with a reference subcarrier spacing. In the case that the PDSCH transmission is transmitted in a sub-slot, the group duration is an integer multiple of a time duration of a sub-slot with a reference subcarrier spacing. In an embodiment of the present application, the reference subcarrier spacing may be defined as the smallest subcarrier spacing (e.g., 15 KHz) of all the subcarrier spacings as specified in 3GPP standard documents. In another embodiment of the present application, the reference subcarrier spacing may be configured by an RRC signaling and the value may be any subcarrier spacing (e.g., 30 KHz) as specified in 3GPP standard documents

In an embodiment of the present application, the value of the fixed or pre-defined group duration may be in units of ms. In such embodiments, the group duration with a value of X represents that the group duration is X ms, which is an integer multiple of a time duration of a slot or sub-slot as specified in 3GPP standard documents. For a same group duration, a group of PDSCH transmissions with a smaller subcarrier spacing may include fewer PDSCH transmissions, and a group of PDSCH transmissions with a larger subcarrier spacing may include more PDSCH transmissions. For example, it is assumed that the value of the fixed or pre-defined group duration is 2.5 (i.e., 2.5 ms) , and the subcarrier spacing of the group of PDSCH transmissions is 30 KHz, then the group duration of the group is 5 times of the time duration of the slot. That is, the group includes 5 PDSCH transmissions in 5 consecutive slots.

In another embodiment of the present application, the value of the fixed or pre-defined group duration may be in units of slots or sub-slots. For example, the value of the fixed or pre-defined group duration may be 5 (i.e., 5 slots or sub-slots) , and then a group includes 5 PDSCH transmissions in 5 consecutive slots (or sub-slots) regardless of the subcarrier spacing of PDSCH transmissions.

For example, the value of the fixed or pre-defined group duration may be 1 ms (i.e., the time duration of a slot with reference subcarrier spacing of 15 KHz) . If the DCI schedules four PDSCH transmissions in four consecutive slots with subcarrier spacing of 30 KHz (i.e., the duration of a slot is 0.5 ms) , then a PDSCH transmission group may contain two PDSCH transmissions in two consecutive slots. That is, the first two PDSCH transmissions scheduled by the DCI are in a first group and the last two PDSCH transmissions scheduled by the DCI are in a second group.

According to some embodiments of the present application, the group duration is configured via an RRC signaling from the BS (e.g., via "Duration" in "PDSCH-Config" as shown in FIG. 4) . That is, the BS may transmit the group duration via an RRC signaling, and the UE may receive the group duration via the RRC signaling. In some embodiments, the group duration is independent of a subcarrier spacing of the plurality of PDSCH transmissions.

In an embodiment of the present application, the group duration may be associated with a channel condition between the BS and the UE. For example, a smaller value of the group duration may be configured to a UE with a relatively higher velocity or with a fast changing channel between the BS and the UE, while a larger value of the group duration may be configured to a UE with a relatively smaller velocity or with a lower changing channel between the BS and the UE.

In such embodiments, the group duration may be a number of slots or sub-slots in each group, an integer multiple of a time duration of one slot or one sub-slot of the plurality of PDSCH transmissions (e.g., in units of ms or in units of slots or sub-slots as described above) , or a time duration of a slot or sub-slot with a reference subcarrier spacing. In some embodiments of the present application, if the group duration is not configured, a default value may be applied. For example, the default value may be one slot, or a time duration of a slot with a default reference subcarrier spacing of 15 KHz, or the default value may be 1 ms.

In some embodiments of the present application, the group duration configured via the RRC signaling from the BS is associated with a subcarrier spacing of the plurality of PDSCH transmissions.

For example, in the case that the group duration is in units of slots or sub-slots, a smaller value of the group duration may be configured to a UE having PDSCH transmissions with a relatively smaller subcarrier spacing, while a larger value of the group duration may be configured to a UE having PDSCH transmissions with a relatively larger subcarrier spacing, because the duration of a slot is smaller for a larger subcarrier spacing and is larger for a smaller subcarrier spacing.

For example, as shown in FIG. 2, for the plurality of PDSCH transmissions with subcarrier spacing of 30 KHz, the group duration may be configured as one slot; for the plurality of PDSCH transmissions with subcarrier spacing of 60 KHz, the group duration may be configured as two slots.

According to some embodiments of the present application, the BS may first configure more than one candidate group duration via an RRC signaling (e.g., via "Duration" in "PDSCH-Config" as shown in FIG. 4) . Consequently, the UE may receive the more than one candidate group duration configured via the RRC signaling. Then, the BS may transmit a MAC CE including a field indicating one of the more than one candidate group duration as the group duration. Consequently, the UE may receive the MAC CE including the field from the BS. The bit width of the field may be determined based on the number of candidate group durations. The field may be newly added to the MAC CE compared to the existing fields as specified in 3GPP standard documents or an existing field in the MAC CE as specified in 3GPP standard documents.

According to some embodiments of the present application, the BS may first configure more than one candidate group duration via an RRC signaling (e.g., via "Duration" in "PDSCH-Config" as shown in FIG. 4) . Consequently, the UE may receive the more than one candidate group duration configured via an RRC signaling. Then, the DCI scheduling the plurality of PDSCH transmissions may include a field indicating one of the more than one candidate group duration as the group duration. Consequently, the UE may receive the field in the DCI. The bit width of the field may be determined based on the number of candidate group durations. The field may be newly added to the DCI compared to the existing fields as specified in 3GPP standard documents or an existing field in the DCI as specified in 3GPP standard documents. For example, the field in the DCI may be a time domain resource allocation (TDRA) field with a new column added in the TDRA table to indicate one of the more than one candidate group duration as the group duration.

For example, it is assumed that the candidate group durations are configured to be {1 ms, 0.5 ms, 0.25 ms} , and a DCI schedules eight type-A PDSCH transmissions with SCS of 60KHz in eight consecutive slots. Moreover, it is assumed that a new field is added in the DCI to indicate the group duration. In this example, the new field may be two bits, and the first three states of the field are used to indicate the three candidate group durations respectively. For example, the field being "00" indicates that the group duration is 1 ms, and thus a group may contain four consecutive PUSCH transmissions and the scheduled eight PUSCH transmissions are divided into two groups; the field being "01" indicates that the group duration is 0.5 ms, and thus a group may contain two consecutive PUSCH transmissions and the scheduled eight PUSCH transmissions are divided into four groups; the field being "10" indicates that the group duration is 0.25 ms, and thus a group may contain one PUSCH transmission and the scheduled eight PUSCH transmissions are divided into eight groups.

In some embodiments of the present application, in the case that the PDSCH transmission is transmitted in a slot, the group duration may be related to a slot. In the case that the PDSCH transmission is transmitted in a sub-slot, the group duration may be related to a sub-slot. Although the above embodiments take the PDSCH transmission transmitted in a slot as an example to illustrate the group duration, persons skilled in the art can understand that the same method may also apply to the case that the PDSCH transmission is transmitted in a sub-slot. In such embodiments, the group duration may be in unis of sub-slots or determined based on the time duration of a sub-slot.

Referring back to FIG. 3, in step 307, the BS may transmit one or more DMRS symbols in each group of the one or more groups determined in step 305. Consequently, in step 308, the UE may receive the one or more DMRS symbols in each group of the one or more groups.

Since channel estimation based on all DMRS symbols in the group could achieve a better performance, the DMRS density for each PDSCH transmission can be reduced to save some overhead. For example, for a PDSCH transmission with a larger subcarrier spacing, the number of DMRS symbols in a PDSCH transmission group will be larger since the group may include more PDSCH transmissions, and then the number of DMRS symbols in each PDSCH transmission in the group could be reduced and the unused symbols could be used for data transmission. The following embodiments may provide methods regarding how to determine the actual locations of DMRS symbols in each group by the BS and the UE. The BS and the UE may use the same principle to determine the locations of the one or more DMRS symbols in each group.

According to some embodiments of the present application, the BS may transmit a proportion via an RRC signaling to the UE (e.g., via "DMRSPattern" in "PDSCH-Config" as shown in FIG. 4) . Consequently, the UE may receive the proportion configured via the RRC signaling from the BS. Then, the BS and the UE may determine location (s) of the one or more DMRS symbols in each group based on the proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table. The DMRS position table may be a table indicating PDSCH DMRS positions as specified in TS 38.211 (e.g., Table 7.4.1.1.2-3 and Table 7.4.1.1.2-4) . In other words, the location (s) of DMRS symbol (s) may be determined based on the methods in Rel-15 or Rel-16. In some embodiments of the present application, the proportion configured by the BS may be some limited values which result in an integer value of DMRS symbols in a PDSCH transmission group. If the proportion is not configured, the UE and the BS may use a default value for the proportion. For example, the default value of the proportion may be 1.

For example, the BS and the UE may first determine the locations of DMRS symbols in each slot (denote as l _k) based on the methods as specified in Rel-15 or Rel-16 (e.g., based on a DMRS position table as specified in TS 38.211) , wherein k =0, 1, 2, …M-1, and M is the number of DMRS symbols in each slot, and thus the locations of DMRS symbols in a group is l _m where m=0, 1, …M*N-1, and N is the number of consecutive PDSCH transmissions in the group. Then, the BS and the UE may determine the actual location (s) of the DMRS symbol (s) in the group (denote as l′ _n) to be l′ _n=l _n/r, where r is the proportion configured by the BS and n =0, 1, …ceil (M*N*r) -1, and determine the actual location (s) of the DMRS symbol (s) in each slot in the group to be l′ _n module L, where L is the number of symbols in a slot.

In some embodiments, if the DMRS is a double-symbol DMRS, l _k is the location index of the first DMRS symbol in the two DMRS symbols, and locations of the double-symbol DMRS in the group may be l′ _k and l′ _k+1.

FIG. 5 illustrates exemplary DMRS symbol patterns in a PDSCH transmission group according to some embodiments of the present application;

Referring to FIG. 5, it is assumed that the group duration is configured as 0.5 ms in time. A DCI schedules eight type-A PDSCH transmissions in eight consecutive slots with subcarrier spacing of 60 KHz, and then a PDSCH transmission group includes two consecutive PDSCH transmissions in two consecutive slots (each slot includes 14 symbols numbered as 0 to 13) . The scheduled eight PDSCH transmissions are divided into four groups and FIG. 5 illustrates one group of the four groups.

In addition, it is assumed that four DMRS symbols including a front-loaded DMRS symbol and three additional DMRS symbols are configured to the UE.

Then, according to Rel-15 or Rel-16 (e.g., based on the DMRS position table as specified in 3GPP standard documents) , there are a total of eight DMRS symbols in a group and the DMRS locations are shown in the top DMRS symbol pattern in FIG. 5. That is, the locations of DMRS symbols in each slot are l _k=2, 5, 8, 11, and thus the locations of DMRS symbols in a group are l _m=2, 5, 8, 11, 16, 19, 22, 25 assuming that the symbols in the group are numbered consecutively.

If the proportion configured to the UE is 1, then the actual locations of DMRS symbols in a group is the same as those determined in Rel-15 or Rel-16, i.e., the locations of DMRS symbols in each slot of the group are l _k=2, 5, 8, 11.

If the proportion configured to the UE is 1/2, then the actual locations of DMRS symbols in the group are l′ _n=l _2n, where n =0, 1, 2, 3. That is, l′ _n=l ₀, l ₂, l ₄, l ₆, which correspond to the first, third, fifth, and seventh locations in the locations l _m=2, 5, 8, 11, 16, 19, 22, 25 as determined based on the methods in Rel-15 and Rel-16. That is, the actual locations of DMRS symbols in the group are l′ _n =2,8, 16, 22 assuming that the symbols in the group are numbered consecutively, and the locations of DMRS symbols in each slot of the group are l′ _k=2, 8 obtained by l′ _n modulo 14.

If the proportion configured to the UE is 1/4, then the actual locations of DMRS symbols in the group are l′ _n=l _4n, where n =0, 1. That is, l′ _n=l ₀, l ₄, which correspond to the first and fifth locations in the locations l _m=2, 5, 8, 11, 16, 19, 22, 25 as determined based on the methods in Rel-15 and Rel-16. That is, the actual locations of DMRS symbols in the group l′ _n = 2, 16 assuming that the symbols in the group are numbered consecutively, and the locations of DMRS symbols in each slot of the group is l′ _k=2 obtained by l′ _n modulo 14.

FIG. 6 illustrates exemplary DMRS symbol patterns in a PDSCH transmission group according to some other embodiments of the present application;

Referring to FIG. 6, it is assumed that: the group duration is configured as 0.5 ms in time; a DCI schedules six type-B PDSCH transmissions in six consecutive sub-slots with subcarrier spacing of 30 KHz, and the duration of each sub-slot is 2 symbols. Then, the group duration of a PDSCH transmission group is one slot (includes 14 symbols numbered as 0 to 13) with subcarrier spacing of 30 KHz, and thus a PDSCH transmission group includes six consecutive PDSCH transmissions in six consecutive sub-slots as shown in FIG. 6.

According to the methods in Rel-15 or Rel-16 (e.g., the DMRS position table as specified in 3GPP standard documents) , there are a total of six DMRS symbols in a group and the DMRS locations are shown in the top DMRS symbol pattern in FIG. 6. That is, the locations of DMRS symbols in a slot are l _k=2, 4, 6, 8, 10, 12, and thus the locations of DMRS symbols in a group is l _m=l _k=2, 4, 6, 8, 10, 12.

If the proportion configured to the UE is 1, then the actual locations of DMRS symbols in a group is the same as those determined in Rel-15 or Rel-16, i.e., the locations of DMRS symbols in each slot of the group is l _k=2, 4, 6, 8, 10, 12.

If the proportion configured to the UE is 1/2, then the actual locations of DMRS symbols in the group are l′ _n=l _2n, where n =0, 1, 2. That is, l′ _n=l ₀, l ₂, l ₄ which correspond to the first, third, and fifth locations in the locations l _m=2, 4, 6, 8, 10, 12 determined based on the methods in Rel-15 or Rel-16. That is, the actual locations of DMRS symbols in the group are l′ _n = 2, 6, 10.

If the proportion configured to the UE is 1/4, then the actual locations of DMRS symbols in the group are l′ _n=l _4n, where n =0, 1. That is, l′ _n=l ₀, l ₄, which correspond to the first and fifth locations in the locations l _m=2, 4, 6, 8, 10, 12. That is, the actual locations of DMRS symbols in the group are l′ _n = 2, 10.

According to some embodiments of the present application, the BS may configure more than one candidate proportion via an RRC signaling (e.g., via "DMRSPattern" in "PDSCH-Config" as shown in FIG. 4) . Consequently, the UE may receive the more than the one candidate proportion configured via the RRC signaling. Then, the BS may transmit a MAC CE including a field indicating one proportion. Consequently, the UE may receive the MAC CE including the field from the BS. The bit width of the field may be determined based on the number of candidate proportions. The field may be newly added to the MAC CE compared to the existing fields as specified in 3GPP standard documents or an existing field in the MAC CE as specified in 3GPP standard documents. Then, the UE and the BS may determine the location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table (e.g., Table 7.4.1.1.2-3 and Table 7.4.1.1.2-4 as specified in TS 38.211) .

According to some embodiments of the present application, the BS may configure more than one candidate proportions via an RRC signaling (e.g., via "DMRSPattern" in "PDSCH-Config" as shown in FIG. 4) . Consequently, the UE may receive the more than one candidate proportion configured via the RRC signaling. Then, the DCI scheduling the plurality of PDSCH transmissions may include a field indicating one proportion. Consequently, the UE may receive the field in the DCI. The bit width of the field may be determined based on the number of candidate proportions. The field may be newly added to the DCI compared to the existing fields as specified in 3GPP standard documents or an existing field in the DCI as specified in 3GPP standard documents. For example, the field in the DCI may be a TDRA field with a new column added in the TDRA table to indicate one of the more than one candidate proportion. Then, the UE and the BS may determine the location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table (e.g., Table 7.4.1.1.2-3 and Table 7.4.1.1.2-4 as specified in TS 38.211) .

According to some embodiments of the present application, the BS and the UE may determine location (s) of the one or more DMRS symbols in each group based on a number of PDSCH transmissions in the group and location (s) of DMRS symbol (s) determined based on a DMRS position table. The DMRS position table may be a table indicating PDSCH DMRS positions (e.g., Table 7.4.1.1.2-3 and Table 7.4.1.1.2-4) as specified in TS 38.211. In other words, the location (s) of DMRS symbol (s) may be determined based on the methods in Rel-15 or Rel-16.

For example, the BS and the UE may first determine the locations of DMRS symbols in each slot (denote as l _k) as specified in Rel-15 or Rel-16 (e.g., based on a DMRS position table as specified in TS 38.211) , wherein k = 0, 1, 2…M-1, and M is the number of DMRS symbols in each slot. Then, the BS and the UE may determine the locations of DMRS symbols in the group (denote as l′ _k) to be l′ _k=N*l _k, where N is the number of consecutive PDSCH transmissions in the group. The locations of DMRS symbols in each slot (denoted as P′ _k) of the group is determined by P′ _k=mod (N*l _k, 14) (i.e., N*l _k modulo 14) . Therefore, once the group duration is determined, the locations of DMRS symbols in the group can be determined.

In some embodiments, if the DMRS is a double-symbol DMRS, the l _k is the location index of the first DMRS symbol in the two DMRS symbols, and locations of double-symbol DMRS in the group may be l′ _k and l′ _k+1.

In an example, the same assumptions in the top figure in FIG. 5 may be used. That is, l _k=2, 5, 8, 11 and a group may include two PDSCH transmission in two consecutive slots. Then, according to the above equation l′ _k=2*l _k, the BS and the UE may determine the locations of DMRS symbols in the group are l′ _k=4, 10, 16, 22 assuming that the symbols in the group are numbered consecutively. The locations of DMRS symbols in each slot (denoted as P′ _k) of the group is determined as P′ _k=4, 10, 2, 8. Accordingly, the locations of DMRS symbols in the group are symbol 4 and symbol 10 in the first slot of the group and symbol 2 and symbol 8 in the second slot of the group.

In another example, if a group include four PDSCH transmissions in four consecutive slots, then according to the above equation l′ _k=4*l _k, the BS and the UE may determine the locations of DMRS symbols in the group are l′ _k=8, 20, 32, 44 assuming that the symbols in the group are numbered consecutively. The locations of DMRS symbols in each slot (denoted as P′ _k) of the group is determined as P′ _k=8, 6, 4, 2. Accordingly, the locations of DMRS symbols in the group are symbol 8 in the first slot of the group, symbol 6 in the second slot of the group, symbol 4 in the third slot of the group, and symbol 2 in the fourth slot of the group.

According to some embodiments of the present application, the BS may transmit location (s) of the one or more DMRS symbols in each group to the UE (e.g., via "DMRSPattern" in "PDSCH-Config" as shown in FIG. 4) . Consequently, the UE may receive the location (s) of the one or more DMRS symbols in each group from the BS.

According to some embodiments of the present application, the BS may transmit location (s) of at least one DMRS symbol in each PDSCH transmission (or in each slot or in each sub-slot) in each group to the UE (e.g., via "DMRSPattern" in "PDSCH-Config" as shown in FIG. 4) . Consequently, the UE may receive the location (s) of the at least one DMRS symbol in each PDSCH transmission (or in each slot or in each sub-slot) in each group from the BS.

FIG. 7 illustrates exemplary DMRS symbol patterns in a PDSCH transmission group according to some other embodiments of the present application.

Referring to FIG. 7, it is assumed that a group includes two PDSCHs transmissions in two consecutive slots (each slot includes 14 symbols numbered as 0 to 13) and three DMRS symbols are configured to the UE.

For example, the BS may transmit DMRS index configuration #1 to the UE. The DMRS index configuration #1 may configure that the locations of DMRS symbols in each slot of each group are symbol 2, symbol 8 and symbol 11. Then, the BS and the UE may determine that the actual locations of the DMRS symbols in the group are symbol 2, symbol 8 and symbol 11 in the first slot and symbol 2, symbol 8 and symbol 11 in the second slot.

In another example, the BS may transmit DMRS index configuration #2 to the UE. The DMRS index configuration #2 may configure that the location of the DMRS symbol in each slot of each group is symbol 5. Then, the BS and the UE may determine that the actual locations of the DMRS symbols in the group are symbol 5 in the first slot and symbol 5 in the second slot.

In yet another example, the BS may transmit DMRS index configuration #3 to the UE. The DMRS index configuration #3 may configure that the locations of DMRS symbols in each group are symbol 2, symbol 13, and symbol 25. Then, the BS and the UE may determine that the actual locations of the DMRS symbols in the group are symbol 2 and symbol 13 in the first slot and symbol 11 in the second slot.

In some embodiments of the present application, if the total number of PDSCH transmissions in consecutive slots or sub-slots scheduled by the DCI can be divided by the number of PDSCH transmissions in a group, then the locations of DMRS symbols in each group may be determined based on the exemplary method described with reference to FIG. 3. However, if the total number of PDSCH transmissions in consecutive slots or sub-slots scheduled by the DCI cannot be divided by the number of PDSCH transmissions in a group, then the last several PDSCH transmissions may be treated as a unique group.

In an embodiment of the present application, the locations of DMRS symbol (s) for the unique group may be determined based on the same methods as illustrated in FIG. 3. In such cases, the performance of channel estimation may decrease and the corresponding PDSCH transmissions may not decode correctly.

In another embodiment of the present application, the locations of DMRS symbol (s) for the unique group may be determined based on the same methods as in Rel-15 and Re-16, which may provide a better performance for the PDSCH transmissions in the unique group.

In step 309, the UE may decode each of the one or more PDSCH transmissions included in each group based on all of the one or more DMRS symbols in the group in response to the indicator. For example, the UE may estimate the channel based on all the DMRS symbols within the group jointly and then interpolate the channel matrix on the symbols of PDSCH transmission within the group to achieve a higher channel estimation performance.

FIG. 8 illustrates a flow chart of another exemplary method for channel estimation based on DMRS according to some other embodiments of the present application. Although the method is illustrated in a system level by a UE and a BS (e.g., UE 105 and BS 101 as illustrated in FIG. 1) , persons skilled in the art can understand that the method implemented in the UE and that implemented in the BS can be separately implemented and incorporated by other apparatus with the like functions.

As shown in FIG. 8, in step 801, the BS may transmit DCI or a configured grant for scheduling a plurality of PUSCH transmissions. In some embodiments of the present application, the plurality of PUSCH transmissions may be a plurality of PUSCH repetitions.

In some embodiments of the present application, the plurality of PUSCH transmissions may be in a plurality of consecutive slots (or in a plurality of consecutive sub-slots) , wherein each PUSCH transmission is in a slot (or in a sub-slot) . In some other embodiments of the present application, not all of the plurality of PUSCH transmissions are transmitted in consecutive slots (or in consecutive sub-slots) . That is, one or more of the plurality of PUSCH transmissions may be in one or more non-consecutive slots (or in one or more non-consecutive sub-slots) , wherein each PUSCH transmission is in a slot (or in a sub-slot) .

Consequently, in step 802, the UE may receive the DCI or configured grant scheduling the plurality of PUSCH transmissions.

In step 803, the BS may determine one or more groups of PUSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PUSCH transmissions of the plurality of PUSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots, and each PUSCH transmission is in a slot or in a sub-slot. Step 803 may occur before, concurrently, or after step 801. Similarly, in step 804, the UE may determine one or more groups of PUSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PUSCH transmissions of the plurality of PUSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots, and each PUSCH transmission is in a slot or in a sub-slot.

The BS and the UE may use the same group duration to determine the one or more groups of PUSCH transmissions. All the methods, principles, and definitions for determining the group duration of the PDSCH transmissions as illustrated in FIG. 3 may also apply for determination of the group duration of the PUSCH transmissions.

In some embodiments of the present application, the group duration is an integer multiple of a time duration of a slot or sub-slot with a reference subcarrier spacing. For example, in the case that the PUSCH transmission is transmitted in a slot, the group duration is an integer multiple of a time duration of a slot with a reference subcarrier spacing. In the case that the PUSCH transmission is transmitted in a sub-slot, the group duration is an integer multiple of a time duration of a sub-slot with a reference subcarrier spacing. In an embodiment of the present application, the reference subcarrier spacing may be defined as the smallest subcarrier spacing (e.g., 15 KHz) of all the subcarrier spacings as specified in 3GPP standard documents. In an embodiment of the present application, the reference subcarrier spacing may be configured as any subcarrier spacing (e.g., 30 KHz) of all the subcarrier spacings as specified in 3GPP standard documents.

In an embodiment of the present application, the fixed value or pre-defined value may be in units of ms. In another embodiment of the present application, the fixed value or pre-defined value may be in units of slots or sub-slots.

According to some embodiments of the present application, the group duration is configured via an RRC signaling from the BS, e.g., via a new field "Duration" in a parameter "PUSCH-Config" as specified in 3GPP standard documents, wherein the "Duration" may be similar to "Duration" in FIG. 4. That is, the BS may transmit the group duration via an RRC signaling, and the UE may receive the group duration via the RRC signaling. In some embodiments, the group duration is independent of a subcarrier spacing of the plurality of PUSCH transmissions. In an embodiment of the present application, the group duration may be associated with a channel condition between the BS and the UE. In some other embodiments, the group duration is associated with the subcarrier spacing of the plurality of PUSCH transmissions.

The group duration may be a number of slots or sub-slots in each group, an integer multiple of a time duration of one slot or one sub-slot of the plurality of PUSCH transmissions (e.g., in units of ms or in units of slots or sub-slots as described above) , or a time duration of a slot or sub-slot with a reference subcarrier spacing. In some embodiments of the present application, if the group duration is not configured, a default value may be applied. For example, the default value may be one slot, or a time duration of a slot with a default reference subcarrier spacing of 15 KHz, or the default value may be 1 ms.

According to some embodiments of the present application, the BS may configure more than one candidate group duration via an RRC signaling, e.g., via a new field "Duration" in a parameter "PUSCH-Config" as specified in 3GPP standard documents, wherein the "Duration" may be similar to "Duration" in FIG. 4. Consequently, the UE may receive the more than one candidate group duration configured via the RRC signaling. Then the BS may transmit a MAC CE including a field indicating one of the more than one candidate group duration as the group duration. Consequently, the UE may receive the MAC CE including the field from the BS. The bit width of the field may be determined based on the number of candidate group durations. The field may be newly added to the MAC CE compared to the existing fields as specified in 3GPP standard documents or an existing field in the MAC CE as specified in 3GPP standard documents.

According to some embodiments of the present application, the BS may first configure more than one candidate group duration via an RRC signaling, e.g., via a new field "Duration" in a parameter "PUSCH-Config" as specified in 3GPP standard documents, wherein the "Duration" may be similar to "Duration" in FIG. 4. Consequently, the UE may receive the more than one candidate group duration configured via the RRC signaling. Then, the DCI or the configured grant scheduling the plurality of PUSCH transmissions may include a field indicating one of the more than one candidate group duration as the group duration. Consequently, the UE may receive the field in the DCI or in the configured grant. The bit width of the field may be determined based on the number of candidate group durations. The field may be newly added to the DCI or configured grant compared to the existing fields as specified in 3GPP standard documents or an existing field in the DCI or the configured grant as specified in 3GPP standard documents. For example, the field in the DCI may be a TDRA field with a new column added in the TDRA table to indicate one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, in the case that the PUSCH transmission is transmitted in a slot, the group duration may be related to a slot. In the case that the PUSCH transmission is transmitted in a sub-slot, the group duration may be related to a sub-slot. Although the above embodiments take the PUSCH transmission transmitted in a slot as an example to illustrate the group duration, persons skilled in the art can understand that the same method may also apply to the case that the PUSCH transmission is transmitted in a sub-slot. In such embodiments, the group duration may be in unis of sub-slots or determined based on the time duration of a sub-slot.

In step 805, the UE may transmit one or more DMRS symbols in each group of the one or more groups. Consequently, in step 806, the BS may receive the one or more DMRS symbols in each group of the one or more groups. The BS and the UE may use the same methods and principles to determine the locations of the one or more DMRS symbols in each group. All the methods, principles, and definitions for determining the locations of one or more DMRS symbols in each group of PDSCH transmissions as illustrated in FIG. 3 may also apply for determining the locations of one or more DMRS symbols in each group of PUSCH transmissions.

According to some embodiments of the present application, the BS may configure a proportion via an RRC signaling to the UE, e.g., via a new field "DMRSPattern" in a parameter "PUSCH-Config" as specified in 3GPP standard documents, wherein the "DMRSPattern" may be similar to "DMRSPattern" in FIG. 4. Consequently, the UE may receive the proportion configured via the RRC signaling from the BS. The BS and the UE may determine location (s) of the one or more DMRS symbols in each group based on the proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table. The DMRS position table may be a table indicating PUSCH DMRS positions (e.g., Table 6.4.1.1.3-3 and Table 6.4.1.1.3-4) as specified in TS 38.211. In other words, the location (s) of DMRS symbol (s) may be determined based on the methods in Rel-15 or Rel-16. In some embodiments of the present application, the proportion configured by the BS may be some limited values which result in an integer value of DMRS symbols in a PUSCH transmission group.

According to some embodiments of the present application, the BS may configure more than one candidate proportion via an RRC signaling, e.g., via a new field "DMRSPattern" in a parameter "PUSCH-Config" as specified in 3GPP standard documents, wherein the "DMRSPattern" may be similar to "DMRSPattern" in FIG. 4. Consequently, the UE may receive the more than one candidate proportion configured via the RRC signaling. Then, the BS may transmit a MAC CE including a field indicating one proportion of the more than one candidate proportion. Consequently, the UE may receive the MAC CE including the field from the BS. The bit width of the field may be determined based on the number of candidate proportions. The field may be newly added to the MAC CE compared to the existing fields as specified in 3GPP standard documents or an existing field in the MAC CE as specified in 3GPP standard documents. Then, the UE and the BS may determine the location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table (e.g., Table 6.4.1.1.3-3 and Table 6.4.1.1.3-4 as specified in TS 38.211) .

According to some embodiments of the present application, the BS may configure more than one candidate proportion via an RRC signaling, e.g., via a new field "DMRSPattern" in a parameter "PUSCH-Config" as specified in 3GPP standard documents, wherein the "DMRSPattern" may be similar to "DMRSPattern" in FIG. 4. Consequently, the UE may receive the more than one candidate proportion configured via an RRC signaling. Then, the DCI or the configured grant scheduling the plurality of PUSCH transmissions may include a field indicating one proportion of the more than one candidate proportion. Consequently, the UE may receive the field in the DCI or the configured grant. The bit width of the field may be determined based on the number of candidate proportions. The field may be newly added to the DCI or the configured grant compared to the existing fields as specified in 3GPP standard documents or an existing field in the DCI or the configured grant as specified in 3GPP standard documents. For example, the field in the DCI may be a TDRA field with a new column added in the TDRA table to indicate one of the more than one candidate group duration values as the group duration. Then, the UE and the BS may determine the location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table (e.g., Table 6.4.1.1.3-3 and Table 6.4.1.1.3-4 as specified in TS 38.211) .

According to some embodiments of the present application, the BS and the UE may determine location (s) of the one or more DMRS symbols in each group based on a number of PUSCH transmissions in the group and location (s) of DMRS symbol (s) determined based on a DMRS position table. The DMRS position table may be a table indicating PUSCH DMRS positions (e.g., Table 6.4.1.1.3-3 and Table 6.4.1.1.3-4) as specified in TS 38.211. In other words, the location (s) of DMRS symbol (s) may be determined based on the methods in Rel-15 or Rel-16.

According to some embodiments of the present application, the BS may transmit location (s) of the one or more DMRS symbols in each group to the UE, e.g., via a new field "DMRSPattern" in a parameter "PUSCH-Config" as specified in 3GPP standard documents, wherein the "DMRSPattern" may be similar to "DMRSPattern" in FIG. 4. Consequently, the UE may receive the location (s) of the one or more DMRS symbols in each group from the BS.

According to some embodiments of the present application, the BS may transmit location (s) of at least one DMRS symbol in each PUSCH transmission in each group to the UE, e.g., via a new field "DMRSPattern" in a parameter "PUSCH-Config" as specified in 3GPP standard documents, wherein the "DMRSPattern" may be similar to "DMRSPattern" in FIG. 4. Consequently, the UE may receive the location (s) of the at least one DMRS symbol in each PUSCH transmission in each group from the BS.

In some embodiments of the present application, if the total number of PUSCH transmissions in consecutive slots or sub-slots scheduled by the DCI or configured grant can be divided by the number of PUSCH transmissions in a group, then the DMRS pattern in each group may be determined based on the exemplary method described with reference to FIG. 8. However, if the total number of PUSCH transmissions in consecutive slots or sub-slots scheduled by the DCI or configured grant cannot be divided by the number of PUSCH transmissions in a group, then the last several PUSCH transmissions may be included in a unique group.

In an embodiment of the present application, the locations of DMRS symbol (s) for the unique group may be determined based on the same methods as illustrated in FIG. 8. In such cases, the performance of channel estimation may decrease and the corresponding PUSCH transmissions may not decode correctly.

In an embodiment of the present application, the locations of DMRS symbol (s) for the unique group may be determined based on the same methods as in Rel-15 and Re-16, which may provide a better performance for the PUSCH transmissions in the unique group.

After receiving the one or more DMRS symbols in each group, the BS may decode the one or more PUSCH transmission in each group of the one or more groups. In some embodiments, the BS may decode each of the one or more PDSCH transmissions included in each group based on all of the one or more DMRS symbols in the group. For example, the BS may estimate the channel based on all the DMRS symbols within the group jointly and then interpolate the channel matrix on the symbols of PUSCH transmission within the group to achieve a higher channel estimation performance. However, in some other embodiments, the BS may not estimate the channel based on all the DMRS symbols within the group jointly, but use legacy methods as specified in 3GPP standard documents to decode the one or more PUSCH transmissions in each group, which depends on the BS's implementation.

FIG. 9 illustrates a simplified block diagram of an exemplary apparatus 900 for channel estimation based on DMRS according to some embodiments of the present application. The apparatus 900 may be or include at least a part of a BS (for example, BS 101) or a UE (for example, UE 105a, UE 105b, or UE 105c) as shown in FIG. 1 or other device with similar functionality.

Referring to FIG. 9, the apparatus 900 may include at least one transmitter 902, at least one receiver 904, and at least one processor 906. The at least one transmitter 902 is coupled to the at least one processor 906, and the at least one receiver 904 is coupled to the at least one processor 906.

Although in this figure, elements such as the transmitter 902, the receiver 904, and the processor 906 are illustrated in the singular, the plural is contemplated unless a limitation to the singular is explicitly stated. In some embodiments of the present application, the transmitter 902 and the receiver 904 may be combined to one device, such as a transceiver. In some embodiments of the present application, the apparatus 900 may further include an input device, a memory, and/or other components.

According to some embodiments of the present application, the apparatus 900 may be a UE. The receiver 904 may receive DCI for scheduling a plurality of PDSCH transmissions. The processor 906 may determine one or more groups of PDSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PDSCH transmissions of the plurality of PDSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots. The receiver 904 may further receive one or more DMRS symbols in each group of the one or more groups. The processor 906 may further decode each of the one or more PDSCH transmissions included in each group based on all of the one or more DMRS symbols in the group in response to an indicator.

In some embodiments of the present application, the indicator is configured by an RRC signaling or indicated by the DCI based on the UE's capability.

In some embodiments of the present application, the group duration is a fixed value or a pre-defined value, and wherein the group duration is an integer multiple of a time duration of a slot or sub-slot with a reference subcarrier spacing.

In some embodiments of the present application, the group duration is configured via an RRC signaling from a BS, and wherein the group duration is independent of a subcarrier spacing of the plurality of PDSCH transmissions.

In some embodiments of the present application, the group duration is configured via an RRC signaling from a BS, and wherein the group duration is associated with a subcarrier spacing of the plurality of PDSCH transmissions.

In some embodiments of the present application, the receiver 904 further receives: more than one candidate group duration configured via an RRC signaling; and a MAC CE including a field indicating one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, the receiver 904 further receives more than one candidate group duration configured via an RRC signaling, and wherein the DCI includes a field indicating one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, the receiver 904 further receives: more than one candidate proportion configured via an RRC signaling; and a MAC CE including a field indicating one proportion of the more than one candidate proportion. The processor 906 determines location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the receiver 904 further receives more than one proportion configured via an RRC signaling, and wherein the DCI includes a field indicating one proportion of the more than one candidate proportion. The processor 906 determines location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the receiver 904 further receives a proportion configured via an RRC signalling. The processor 906 determines location (s) of the one or more DMRS symbols in each group based on the proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the processor 906 determines location (s) of the one or more DMRS symbols in each group based on a number of PDSCH transmissions in the group and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the receiver 904 further receives location (s) of the one or more DMRS symbols in each group or location (s) of at least one DMRS symbol in each PDSCH transmission in each group configured via an RRC signaling.

According to some embodiments of the present application, the apparatus 900 may be a BS. The transmitter 902 may transmit DCI for scheduling a plurality of PDSCH transmissions. The processor may determine one or more groups of PDSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PDSCH transmissions of the plurality of PDSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots. The transmitter 902 further transmits one or more DMRS symbols in each group of the one or more groups, and transmits an indicator based on a capability of a UE to indicate the UE to decode each of the one or more PDSCH transmissions in each group based on all of the one or more DMRS symbols in the group.

In some embodiments of the present application, wherein the indicator is transmitted via an RRC signaling or transmitted in the DCI.

In some embodiments of the present application, wherein the group duration is a fixed value or a pre-defined value, and wherein the group duration is an integer multiple of a time duration of a slot or sub-slot with a reference subcarrier spacing.

In some embodiments of the present application, wherein the transmitter 902 further transmits the group duration via an RRC signaling to the UE, and wherein the group duration is independent of a subcarrier spacing of the plurality of PDSCH transmissions.

In some embodiments of the present application, the transmitter 902 further transmits the group duration via an RRC signaling to the UE, and wherein the group duration is associated with a subcarrier spacing of the plurality of PDSCH transmissions.

In some embodiments of the present application, wherein the group duration is a number of slots or sub-slots in each group, an integer multiple of a time duration of one slot or one sub-slot of the plurality of PDSCH transmissions, or a time duration of a slot with a sub-slot with a reference subcarrier spacing.

In some embodiments of the present application, the transmitter 902 further transmits: more than one candidate group duration via an RRC signaling; and a MAC CE including a field indicating one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, the transmitter 902 further transmits more than one candidate group duration via an RRC signaling, and wherein the DCI includes a field indicating one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, the transmitter 902 further transmits: more than one candidate proportion via an RRC signaling; and a MAC CE including a field indicating one proportion of the more than one candidate proportion; wherein the processor determines location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the transmitter 902 further transmits more than one proportions via an RRC signaling, and wherein the DCI includes a field indicating one proportion of the more than one candidate proportion, and wherein the processor determines location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the transmitter 902 further transmits a proportion via an RRC signaling, and wherein the processor determines location (s) of the one or more DMRS symbols in each group based on the proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the transmitter 902 further transmits location (s) of the one or more DMRS symbols in each group or location (s) of at least one DMRS symbol in each PDSCH transmission in each group via an RRC signaling.

According to some other embodiments of the present application, the apparatus may be a UE. The receiver 904 may receive DCI or a configured grant for scheduling a plurality of PUSCH transmissions. The processor 906 may determine one or more groups of PUSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PUSCH transmissions of the plurality of PUSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots. The transmitter 902 may transmit one or more DMRS symbols in each group of the one or more groups.

In some embodiments of the present application, wherein the group duration is configured via an RRC signaling from a BS, and wherein the group duration is independent of a subcarrier spacing of the plurality of PUSCH transmissions.

In some embodiments of the present application, wherein the group duration is configured via an RRC signaling from a BS, and wherein the group duration is associated with a subcarrier spacing of the plurality of PUSCH transmissions.

In some embodiments of the present application, wherein the group duration is a number of slots or sub-slots in each group, an integer multiple of a time duration of one slot or one sub-slot of the plurality of PUSCH transmissions, or a time duration of a slot or a sub-slot with a reference subcarrier spacing.

In some embodiments of the present application, the receiver 904 further receives more than one candidate group duration configured via an RRC signaling, and wherein the DCI or configured grant includes a field indicating one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, the receiver 904 further receives more than one proportion configured via an RRC signaling, and wherein the DCI or configured grant includes a field indicating one proportion of the more than one candidate proportion. The processor 906 determines location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the processor 906 determines location (s) of the one or more DMRS symbols in each group based on a number of PUSCH transmissions in the group and location (s) of DMRS symbol (s) based on a DMRS position table.

According to some embodiments of the present application, the apparatus 900 may be a BS. The transmitter 902 may transmit, to a UE, DCI or a configured grant for scheduling a plurality of PUSCH transmissions. The processor 906 may determine one or more groups of PUSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PUSCH transmissions of the plurality of PUSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots. The receiver 904 may receive one or more DMRS symbols in each group of the one or more groups.

In some embodiments of the present application, wherein the transmitter further transmits the group duration via an RRC signaling to the UE, and wherein the group duration is independent of a subcarrier spacing of the plurality of PDSCH transmissions.

In some embodiments of the present application, the transmitter 902 further transmits more than one candidate group duration via an RRC signaling, and wherein the DCI or configured grant includes a field indicating one of the more than one candidate group duration as the group duration.

In some embodiments of the present application, the transmitter 902 further transmits: more than one candidate proportion via an RRC signaling; and a MAC CE including a field indicating one proportion of the more than one candidate proportion. The processor 906 determines location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the transmitter 902 further transmit more than one proportion via an RRC signaling, and wherein the DCI or configured grant includes a field indicating one proportion of the more than one candidate proportion. The processor 906 determines location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the transmitter 902 further transmits a proportion via an RRC signalling. The processor 906 determines location (s) of the one or more DMRS symbols in each group based on the proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the processor 906 determines location (s) of the one or more DMRS symbols in each group based on a number of PUSCH transmissions in the group and location (s) of DMRS symbol (s) determined based on a DMRS position table.

In some embodiments of the present application, the apparatus 900 may further include at least one non-transitory computer-readable medium. In some embodiments of the present disclosure, the non-transitory computer-readable medium may have stored thereon computer-executable instructions to cause the processor 906 to implement any of the methods as described above. For example, the computer-executable instructions, when executed, may cause the processor 906 to interact with the transmitter 902 and/or the receiver 904, so as to perform operations of the methods, e.g., as described with respect to FIGS. 3-8.

The method according to embodiments of the present application can also be implemented on a programmed processor. However, the controllers, flowcharts, and modules may also be implemented on a general purpose or special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit elements, an integrated circuit, a hardware electronic or logic circuit such as a discrete element circuit, a programmable logic device, or the like. In general, any device on which resides a finite state machine capable of implementing the flowcharts shown in the figures may be used to implement the processor functions of this application. For example, an embodiment of the present application provides an apparatus for channel estimation based on DMRS, including a processor and a memory. Computer programmable instructions for implementing a method for channel estimation based on DMRS are stored in the memory, and the processor is configured to perform the computer programmable instructions to implement the method for channel estimation based on DMRS. The method for channel estimation based on DMRS may be any method as described in the present application.

An alternative embodiment preferably implements the methods according to embodiments of the present application in a non-transitory, computer-readable storage medium storing computer programmable instructions. The instructions are preferably executed by computer-executable components preferably integrated with a network security system. The non-transitory, computer-readable storage medium may be stored on any suitable computer readable media such as RAMs, ROMs, flash memory, EEPROMs, optical storage devices (CD or DVD) , hard drives, floppy drives, or any suitable device. The computer-executable component is preferably a processor but the instructions may alternatively or additionally be executed by any suitable dedicated hardware device. For example, an embodiment of the present application provides a non-transitory, computer-readable storage medium having computer programmable instructions stored therein. The computer programmable instructions are configured to implement a method for channel estimation based on DMRS according to any embodiment of the present application.

While this application has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations may be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the disclosed embodiments. For example, one of ordinary skill in the art of the disclosed embodiments would be enabled to make and use the teachings of the application by simply employing the elements of the independent claims. Accordingly, embodiments of the application as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the application.

Claims

A user equipment (UE) , comprising:

a receiver that receives downlink control information (DCI) for scheduling a plurality of physical downlink shared channel (PDSCH) transmissions;

a processor that is coupled to the receiver and determines one or more groups of PDSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PDSCH transmissions of the plurality of PDSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots; and

a transmitter coupled to the processor;

wherein the receiver further receives one or more demodulation reference signal (DMRS) symbols in each group of the one or more groups, and

wherein the processor further decodes each of the one or more PDSCH transmissions included in each group based on all of the one or more DMRS symbols in the group in response to an indicator.
The UE of Claim 1, wherein the indicator is configured by a radio resource control (RRC) signaling or indicated by the DCI based on the UE's capability.
The UE of Claim 1, wherein the group duration is a fixed value or a pre-defined value.
The UE of Claim 1, wherein the group duration is configured via an RRC signaling from a base station (BS) .
The UE of Claim 1,

wherein the receiver further receives more than one candidate group duration configured via an RRC signaling; and

wherein the DCI includes a field indicating one of the more than one candidate group duration as the group duration or wherein the receiver further receives a medium access control (MAC) control element (CE) including a field indicating one of the more than one candidate group duration as the group duration.
The UE of Claim 1,

wherein the receiver further receives more than one candidate proportion configured via an RRC signaling;

wherein the DCI includes a field indicating one proportion of the more than one candidate proportion or wherein the receiver further receives a medium access control (MAC) control element (CE) including a field indicating one proportion of the more than one candidate proportion; and

wherein the processor determines location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.
The UE of Claim 1, wherein the receiver further receives a proportion configured via an RRC signaling, and wherein the processor determines location (s) of the one or more DMRS symbols in each group based on the proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.
The UE of Claim 1, wherein the processor determines location (s) of the one or more DMRS symbols in each group based on a number of PDSCH transmissions in the group and location (s) of DMRS symbol (s) determined based on a DMRS position table.
The UE of Claim 1, wherein the receiver further receives location (s) of the one or more DMRS symbols in each group or location (s) of at least one DMRS symbol in each PDSCH transmission in each group configured via an RRC signaling.
A base station (BS) , comprising:

a transmitter that transmits downlink control information (DCI) for scheduling a plurality of physical downlink shared channel (PDSCH) transmissions;

a processor that is coupled to the transmitter and determines one or more groups of PDSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PDSCH transmissions of the plurality of PDSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots; and

a receiver coupled to the processor;

wherein the transmitter further transmits one or more demodulation reference signal (DMRS) symbols in each group of the one or more groups, and

wherein the transmitter transmits an indicator based on a capability of a user equipment (UE) to indicate the UE to decode each of the one or more PDSCH transmissions in each group based on all of the one or more DMRS symbols in the group.
A user equipment (UE) , comprising:

a receiver that receives downlink control information (DCI) or a configured grant for scheduling a plurality of physical uplink shared channel (PUSCH) transmissions;

a processor that is coupled to the receiver and determines one or more groups of PUSCH transmissions based on a group duration, wherein each group of the one or more groups includes one or more PUSCH transmissions of the plurality of PUSCH transmissions in one or more consecutive slots or one or more consecutive sub-slots; and

a transmitter that is coupled to the processor and transmits one or more demodulation reference signal (DMRS) symbols in each group of the one or more groups.
The UE of Claim 11, wherein the group duration is configured via an RRC signaling from a BS.
The UE of Claim 11,

wherein the receiver further receives more than one candidate group duration configured via an RRC signaling; and

wherein the DCI or configured grant includes a field indicating one of the more than one candidate group duration as the group duration or wherein the receiver further receives a medium access control (MAC) control element (CE) including a field indicating one of the more than one candidate group duration as the group duration.
The UE of Claim 11,

wherein the receiver further receives more than one candidate proportion configured via an RRC signaling;

wherein the DCI or configured grant includes a field indicating one proportion of the more than one candidate proportion or wherein the receiver further receives a medium access control (MAC) control element (CE) including a field indicating one proportion of the more than one candidate proportion; and

wherein the processor determines location (s) of the one or more DMRS symbols in each group based on the one proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.
The UE of Claim 11, wherein the receiver further receives a proportion configured via an RRC signaling, and wherein the processor determines location (s) of the one or more DMRS symbols in each group based on the proportion and location (s) of DMRS symbol (s) determined based on a DMRS position table.