JP2021177648A - Method by user device and base station - Google Patents

Abstract

To provide a method for communications between a user device and a base station, which is related to a communication process in a radio communication system based on short TTI.SOLUTION: The method includes: receiving an uplink demodulation reference signal (DMRS) from a user device in an uplink transmission time interval (TTI) of an uplink sub-frame which supports two or more uplink TTIs. At least one uplink TTI supported by the uplink sub-frame is formed to send uplink control information and/or uplink data alone without having an uplink DMRS.SELECTED DRAWING: Figure 7A

Description

The present disclosure relates to wireless communications in general, and particularly to methods and devices for transmitting demodulation reference signals (DMRSs) based on shortened Transmission Time Intervals (TTIs) in communication systems.

This section is intended to provide a background for various embodiments of the invention described in the present disclosure. The description herein may include concepts that can be pursued, but not necessarily previously conceived or pursued. Accordingly, unless otherwise indicated herein, what is described in this section is incorporated in this section rather than the prior art in the description and / or claims of the present disclosure. It is not recognized as prior art.

The long-term evolution (LTE) system, launched by the 3GPP (third generation partnership project), is currently high data rate, low latency, packet optimization, and improved system capacity. And is regarded as a new wireless interface and wireless network architecture that provides coverage. In the LTE system, the evolved universal terrestrial radio access network (E-UTRAN) includes a plurality of evolved nodes B (eNB: evolved Node-B), and the user equipment (UE: user equipment). Communicates with multiple mobile stations called. The E-UTRAN radio protocol stack includes radio resource control (RRC), packet data convergence protocol (PDCP), radio link control (RLC), and media access control. It is given including a layer (MAC: media access control) and a physical layer (PHY: physical).

In a 3GPP radio access network (RAN) LTE system, the node is an E-UTRAN (Evolved Universal Terrestrial Radio Access Network) node B (generally also referred to as an evolved node B, enhanced node B, eNodeB, or eNB). And can be a combination of a radio network controller (RNC). It communicates with a wireless device known as a user equipment (UE). Downlink (DL) transmission can be communication from a node (eg, eNodeB) to a wireless device (eg, UE). Also, uplink (UL) transmission can be communication from a wireless device to a node.

In LTE, data can be transmitted from the UE to the eNodeB via a physical uplink shared channel (PUSCH). The PUSCH carries scheduled data traffic and possible control signaling. The PUSCH can be carried in a subframe of the wireless frame. Further, the data can be transmitted from the eNodeB to the UE via the physical downlink shared channel (PDSCH). PDSCH is also delivered in 1 ms subframe and downlink scheduled over each TTI. The UE acknowledges / does not acknowledge (ACK) to the base station via a physical uplink control channel (PUCCH) that can be used to carry uplink control information. acknowledgment) You can send feedback. Traditionally, a 1 millisecond (ms) subframe containing 14 symbols can only allow 1 ms TTI, which is the minimum time unit for scheduling DL and UL transmissions.

Demodulated Reference Signals (DMRS) are Time Division Duplexing (TDD) and / and Frequency Division Duplexing (FDD) radio communication systems to determine the quality of downlink and uplink channels. Used in.

According to the current 3GPP specifications, the DMRS signal is then composed of PUCCH / PUSCH / PDSCH channels. 1A-1C schematically show an exemplary pattern of DMRS in a PUCCH, PUSCH, PDSCH configuration of an existing LTE system. For all TTIs that support 14 symbols, multiple symbols need to be assigned to the DMRS transmission.

At the 3GPP RAN # 67 meeting, a study item on "Examination of LTE latency reduction technology" was approved. For RAN1, reduction of TTI and reduction of processing time need to be considered and documented at least from the following perspectives:
The study feasibility and performance of the TTI length between 0.5 ms and one OFDM symbol will be examined, taking into account the effects on the reference signal and the physical layer control signal;
-Backward compatibility must be maintained, thus allowing normal operation of the pre-Rel 13 UE in the same carrier.

Nevertheless, in this study, "By shortening the TTI length, the network can schedule the UE faster and the round trip time (RTT) can be shortened. , Increasing TCP throughput. Shortening the TTI length can also increase the system capacity for small data transmissions. "

Therefore, in wireless communication systems, it is necessary to provide a solution for DMRS communication based on short TTI.

Since the number of symbols in one TTI is reduced from the point of view of latency reduction technology, DMRS overhead should be considered especially for short TTIs containing 1 or 2 symbols when DMRS signals are introduced in each TTI. Must be. Moreover, the channel state may not change much, especially for continuous scheduling or short TTI at high frequencies. In that sense, some DMRS may not be needed when demodulating control information or data.

To solve the above problems, embodiments of one or more methods and devices according to the present disclosure are intended to provide a solution for DMRS communication based on shortened TTI. Other features and advantages of the embodiments of the present disclosure will also be understood from the following description of the particular embodiment by reading in conjunction with the accompanying drawings showing the principles of the embodiments of the present disclosure.

According to the first aspect of the present disclosure, a method for communication by a base station operating in a wireless communication system is provided. The method comprises receiving an uplink demodulation reference signal (DMRS) at the TTI of an uplink subframe that supports two or more uplink transmission time intervals (TTIs). At least one uplink TTI supported by the uplink subframe is configured to transmit only uplink control information and / or uplink data without uplink DMRS (without uplink DMRS). Will be done.

According to the second aspect of the present disclosure, a method for communication by a base station operating in a wireless communication system is provided. The method comprises transmitting a downlink DMRS to a user apparatus in a downlink TTI of a downlink subframe that supports two or more TTIs. At least one downlink TTI supported by the downlink subframe is configured to transmit only downlink control information and / or downlink data without downlink DMRS (without downlink DMRS). Will be done.

According to a third aspect of the present disclosure, there is provided a method for communication by a user device operating in a wireless communication system. The method transmits an uplink demodulation reference signal (DMRS) to a base station in an uplink TTI of an uplink subframe that supports two or more uplink transmission time intervals (TTIs). Including doing. At least one uplink TTI supported by the uplink subframe is configured to transmit only the uplink control information and / or the uplink data without the uplink DMRS.

According to a fourth aspect of the present disclosure, a method for communication by a user device operating in a wireless communication system is provided. The method comprises receiving a downlink DMRS from a base station in a downlink TTI of a downlink subframe that supports two or more downlink TTIs. At least one downlink TTI after the downlink TTI to which the downlink DMRS is received is configured not to transmit any downlink DMRS.

According to a further aspect of the present disclosure, a base station is provided. The base station includes a transmitter and a receiver configured to perform the functions described above in the first and second aspects of the present disclosure.

According to a further aspect of the present disclosure, a user device is provided. The user device includes a transmitting unit and a receiving unit configured to include the above-mentioned functions in the third and fourth aspects of the present disclosure.

According to a further aspect of the present disclosure, a base station is provided. The base station comprises processing means configured to perform a method for communication by the base station according to any of the various embodiments of the present disclosure.

According to a further aspect of the present disclosure, a user device is provided. The user device comprises processing means configured to perform a method for communication by the user device according to any of the various embodiments of the present disclosure.

Inventional features that are considered to be features of the present invention are described in the appended claims. However, the present invention, its implementation modes, other objectives, features and advantages will be better understood by reading the following detailed description of exemplary embodiments with reference to the accompanying drawings.

FIG. 1A schematically shows an exemplary DMRS pattern composed of PUCCH for a wireless communication system. FIG. 1B schematically shows an exemplary DMRS pattern configured with PUSCH for a wireless communication system. FIG. 1C schematically shows an exemplary DMRS pattern composed of PDSCHs for wireless communication systems.

FIG. 2A is a diagram schematically showing an exemplary DMRS structure applicable to a plurality of short TTIs according to an embodiment of the present disclosure. FIG. 2B is a diagram schematically showing an exemplary DMRS structure applicable to a plurality of short TTIs according to an embodiment of the present disclosure.

FIG. 3A is a diagram schematically showing an exemplary DMRS structure having a candidate DMRS position and a fixed DMRS position according to one or more embodiments of the present disclosure. FIG. 3B is a diagram schematically showing an exemplary DMRS structure having a candidate DMRS position and a fixed DMRS position according to one or more embodiments of the present disclosure.

FIG. 4A is a diagram schematically showing an exemplary DMRS structure suitable for one symbol-based TTI according to one or more embodiments of the present disclosure. FIG. 4B is a diagram schematically showing an exemplary DMRS structure suitable for one symbol-based TTI according to one or more embodiments of the present disclosure. FIG. 4C is a diagram schematically showing an exemplary DMRS structure suitable for one symbol-based TTI according to one or more embodiments of the present disclosure.

FIG. 5 is a diagram schematically showing a method for communication by a base station according to one or more embodiments of the present disclosure.

FIG. 6 is a diagram schematically showing a method for communication by a user device according to one or more embodiments of the present disclosure.

FIG. 7A is a diagram schematically showing exemplary UL and DL subframes with uplink DMRS according to one or more embodiments of the present disclosure. FIG. 7B is a diagram schematically showing exemplary UL and DL subframes with uplink DMRS according to one or more embodiments of the present disclosure. FIG. 7C is a diagram schematically showing exemplary UL and DL subframes with uplink DMRS according to one or more embodiments of the present disclosure.

FIG. 8 is a diagram schematically showing exemplary UL and DL subframes with uplink DMRS according to a further embodiment of the present disclosure.

FIG. 9 is a diagram schematically showing an exemplary method for demodulating a PUCCH channel based on the uplink DMRS according to one or more embodiments of the present disclosure.

FIG. 10A is a diagram schematically showing exemplary UL and DL subframes with uplink DMRS according to one or more embodiments of the present disclosure. FIG. 10B is a diagram schematically showing exemplary UL and DL subframes with uplink DMRS according to one or more embodiments of the present disclosure. FIG. 10C is a diagram schematically showing exemplary UL and DL subframes with uplink DMRS according to one or more embodiments of the present disclosure.

FIG. 11 is a diagram schematically showing a method for communication by a base station according to one or more embodiments of the present disclosure.

FIG. 12 is a diagram schematically showing a method for communication by a user device according to one or more embodiments of the present disclosure.

FIG. 13A is a diagram schematically showing exemplary UL and DL subframes with downlink DMRS according to one or more embodiments of the present disclosure. FIG. 13B is a diagram schematically showing exemplary UL and DL subframes with downlink DMRS according to one or more embodiments of the present disclosure.

FIG. 14 is a block diagram schematically showing a base station according to one or more embodiments of the present disclosure.

FIG. 15 is a block diagram schematically showing a user device according to one or more embodiments of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the following description, many specific details are given to provide a more comprehensive understanding of the present disclosure. However, it will be apparent to those skilled in the art that the implementation of the present invention does not have to have these details. Furthermore, it should be understood that the present invention is not limited to the particular embodiments introduced herein. Conversely, any combination of the following features and elements may be considered for implementing and implementing the present invention, whether or not they contain different embodiments. For example, for purposes of illustration, described below in the context of a 5G cellular communication system, one of ordinary skill in the art will also apply one or more embodiments of the present disclosure to various other types of cellular communication systems. You will recognize that you can. Accordingly, the following aspects, features, embodiments, and advantages are understood as elements or limitations of the appended claims for explanatory purposes only and unless expressly specified in the claims. Should not be.

A user device (UE) may include an access terminal, a subscriber station, a subscriber unit, a mobile station, a remote station, a remote terminal, a user terminal, a user agent, a user device, a user station, or some other term. good. Alternatively, user equipment (UE) is implemented as an access terminal, subscriber station, subscriber unit, mobile station, remote station, remote terminal, user terminal, user agent, user device, user station, or some other term. May be done or may be known.

In some implementations, the user equipment is a cellular phone, cordless phone, Session Initiation Protocol (SIP) phone, personal digital assistant (PDA), handheld device with wireless connectivity, station (STA:). Station), or some other suitable processing device connected to a wireless modem. Thus, one or more aspects taught herein are telephones (eg, cellular phones or smartphones), computers (eg, laptops), portable communication devices, portable computing devices (eg, personal data assistants), and more. It may be incorporated into an entertainment device (eg, a music or video device, or satellite radio), a Global Positioning System device, or any other suitable device configured to communicate via a wireless or wired modem. In some embodiments, the node is a wireless node. Such wireless nodes may provide connectivity for, for example, networks (eg, wide area networks such as the Internet or cellular networks), or connectivity to such networks, via wired or wireless communication links.

Base stations (BS) include NodeB, wireless network controller (RNC: Radio Network Controller), eNodeB (eNB), base station controller (BSC: Base Station Controller), base transceiver station (BTS: Base Transceiver Station), transceiver. Function (TF: Transceiver Function), radio router, radio transceiver, basic service set (BSS: Basic Service Set), extended service set (ESS: Extended Service Set), radio base station (RBS: Radio Base Station), or some Other terms may be included. Alternatively, the base station (BS) can be a NodeB, a wireless network controller (RNC), an eNodeB (eNB), a base station controller (BSC), a base transceiver station (BTS), a transceiver function (TF), a wireless router, or a wireless transceiver. , Basic service set (BSS), extended service set (ESS), radio base station (RBS), or may be implemented or known as some other term.

As mentioned above, it is necessary to reduce the number of symbols of one UL / DL TTI in order to reduce the latency. However, in existing LTE technology, DMRS is introduced for each TTI and occupies at least one symbol. The DMRS overhead consumes significant radio resources both in the time and frequency domain, especially provided that the short TTI contains one or two symbols. Moreover, channel state may not change much between short TTIs, especially for continuous scheduling or at high frequencies. In that sense, configuring DMRS with various physical channels in each TTI can cause radio resource efficiency issues.

To solve the above problems, embodiments of one or more methods and devices according to the present disclosure are intended to provide a solution for DMRS communication based on shortened TTI. In this solution, the UL / DL DMRS transmits independently of the transmission of the respective physical channels such as the physical uplink shared channel (PUSCH), the physical uplink control channel (PUCCH), and the physical downlink shared channel (PDSCH). can do. In other words, the transmission of DMRS is controlled by means separate from the means that control the transmission of each physical channel. According to various embodiments of the present disclosure, the DMRS may be triggered to be dynamically transmitted. According to additional or alternative embodiments of the present disclosure, the transmission of DMRS is configured in one or more periodic patterns, which may consist of higher layer signaling. Means for independently controlling DMRS transmission can be applied in any suitable combination method. As a result, for example, some TTIs may be transmitted without DMRS in the short TTI, and some TTIs may be controlled to transmit additional DMRS at the candidate DMRS position.

2A and 2B are diagrams schematically showing an exemplary DMRS structure applicable to a plurality of short TTIs according to an embodiment of the present disclosure. For the purposes of brevity, it is assumed that the TTI described with reference to FIGS. 2A and 2B contains two or more symbols.

FIG. 2A shows a subframe structure in which DMRS can be controlled to be transmitted only in some TTIs, but DMRSs are not transmitted in some other TTIs.

The dashed block 201 illustrates an exemplary structure of TTI with DMRS transmission. In one example, the DMRS may occupy one or more symbols of one TTI, and the remaining symbols of that TTI transmit data or control information, depending on the type of physical channel currently scheduled for this TTI. Can be used to do. In another example, the DMRS may be sparse in the time and / or frequency domain, for example, occupying part of the frequency resources of one or more symbols in one TTI. The remaining symbols of the TTI can be used to transmit data or control information, depending on the particular type of physical channel currently scheduled for this TTI.

The dashed block 202 provides an exemplary structure of TTI without DMRS. If there is no DMRS transmission in one TTI, in one example, the DMRS position may be reserved or left empty, even if the remaining symbols of that TTI are occupied by data or control information. good. In this example, these predefined radio resources are dedicated to transmitting DMRS and cannot be used to transmit data or control information. If DMRS is not actually transmitted in this TTI, it would be more efficient if the data or control information could use these radio resources for DMRS transmission. In that example, all symbols of TTI can be assigned to data or control information transmission. It should be understood that the DMRS structure for short TTI may be designed in any suitable combination of resource reservation mode and resource sharing mode described above.

FIG. 2B shows a subframe structure in which additional DMRS transmissions can be activated more than other normal TTIs in some TTIs.

As shown in FIG. 2B, candidate DMRS positions may be predefined in TTI. If the DMRS transmission is triggered or configured by higher layer signaling, one or more DMRS positions may be selected from these candidate DMRS positions based on the trigger information or higher layer signaling. For backwards compatibility, the new DMRS structure may support fixed DMRS positions specified in existing LTE (as described with reference to FIGS. 1A-1C). If additional DMRS is triggered or configured by higher layer signaling, additional DMRS may be transmitted as needed in addition to the fixed DMRS position.

3A and 3B are diagrams illustrating an outline of an exemplary DMRS structure having a candidate DMRS position and a fixed DMRS position according to one or more embodiments of the present disclosure.

In some implementations, one additional DMRS can be set (either by being triggered or periodically) if frequency offset estimation is required. Otherwise, only the original fixed DMRS will be transmitted (history frequency offsets can be reused). FIG. 3A is a subframe structure having a fixed DMRS position such as a legacy DMRS position. As shown in FIG. 3A, one TTI is composed of four symbols, and one symbol of fixed DMRS is shared by two consecutive TTIs. Additional DMRS positions may be placed at each TTI. DMRS transmissions may be activated at some additional DMRS positions, for example by a separate control means, such as a trigger by a specified trigger or a transmission in a cyclical manner set by higher layer signaling. For example, as shown in FIG. 3B, additional DMRS positions in the first TTI are configured to transmit DMRS. The next TTI shown is configured so that DMRS is not transmitted at additional DMRS positions so that DMRS is transmitted only at these TTI fixed positions.

4A-4C are diagrams schematically showing exemplary DMRS structures suitable for one-symbol-based TTI according to one or more embodiments of the present disclosure.

If the DMRS consists of only one symbol in one TTI, the DMRS may be multiplexed with data or control information (eg, PUSCH, PUSCH, PDSCH) in the same symbol. 4A and 4B show two different multiplexing methods for DMRS and data / control information. In the example shown in FIG. 4A, a one-symbol-based TTI with DMRS multiplexed with data / control information may have a structure different from those symbols without DMRS. The one-symbol-based TTI occupies more frequency resources than a symbol without a multiplexed DMRS. In the example of FIG. 4B, a one-symbol-based TTI with DMRS is possible as an alternative.

FIG. 4C shows another example in which DMRS is transmitted on a symbol different from the physical channel (PUSCH / PUCCH / PDSCH). As shown in FIG. 4C, DMRS may occupy all resources of a one-symbol-based TTI and be transmitted before data or control information. In a one-symbol-based TTI, there is no multiplexing between data / control information and DMRS.

More generally, in an L-symbol-based TTI, the number of DMRSs (K, K> = 0) may be dynamically set, for example, by downlink control information (DCI) and /. Alternatively, for example, it may be set semi-statically by higher layer signaling. The LK symbol is then set for data / control information. Alternatively, in one TTI, the DMRS is sparse and can be multiplexed with data / control information in the frequency domain. In some implementations, different TTIs or TTI groups may have an independent number of DMRSs. For example, the TTI group may be a continuous TTI or a periodic TTI with different cycles / or offsets. Further, the TTI group size may be set, for example, may be dynamically instructed by DCI, or may be semi-statically instructed by upper layer information. Also, an independent number of DMRSs may be set dynamically by DCI and / or semi-statically by higher layer signaling. As mentioned above, DMRS may be set in some candidate positions. Additional or alternative, the newly triggered DMRS may have a pattern different from the configured pattern.

FIG. 5 is a diagram schematically showing a method 500 for communication by a base station according to one or more embodiments of the present disclosure. Method 500 in FIG. 5 describes the process of uplink DMRS transmission from the perspective of a base station. As shown in FIG. 5, in step S510, the base station receives the uplink DMRS from the user apparatus in the uplink TTI of the uplink subframe. Uplink subframes support two or more uplink TTIs.

The transmission of the uplink DMRS is controlled independently of the transmission of the uplink physical channel. At least one uplink TTI supported by the uplink subframe may be configured to transmit only the uplink control information and / or the uplink data without the uplink DMRS. Any suitable DMRS structure may be applied to the uplink DMRS as described with reference to FIGS.

According to one or more embodiments of the present disclosure, method 500 transmits an uplink DMRS trigger to a user apparatus to enable transmission of the uplink DMRS in the uplink TTI of the uplink subframe. (Shown) may be further included. Uplink DMRS triggers may be carried in the downlink TTI of the downlink subframe that supports two or more downlink TTIs. As an example, the uplink DMRS trigger may be one or more bits to allow transmission and / or configuration of the corresponding DMRS. According to one or more embodiments of the present disclosure, the uplink DMRS trigger may include information on how to configure the uplink DMRS transmitted from the user equipment to the base station. As discussed with reference to FIGS. 2-4, some types of DMRS configuration information may be included in the trigger. As an example, an uplink DMRS trigger may include, but is not limited to, at least one of the information shown below: the number of symbols occupied by the uplink DMRS; the time of the uplink DMRS to be triggered; Resource allocation for the uplink DMRS; and candidate symbol positions occupied by the uplink DMRS in the uplink TTI.

According to one or more additional or alternative embodiments of the present disclosure, the uplink DMRS may be periodically received from the user equipment. The uplink DMRS is controlled to be transmitted in a periodic manner, for example, by higher layer signaling.

FIG. 6 is a diagram schematically showing a method for communication by a user device according to one or more embodiments of the present disclosure. Method 600 in FIG. 6 describes the process of uplink DMRS transmission from the point of view of the user equipment. As shown in FIG. 6, in step S610, the user apparatus transmits the uplink DMRS to the base station at the UL subframe uplink TTI that supports two or more uplink TTIs.

The transmission of the uplink DMRS is controlled independently of the transmission of the uplink physical channel. At least one uplink TTI supported by the uplink subframe may be configured to transmit only the uplink control information and / or the uplink data without the uplink DMRS. The DMRS may employ any suitable DMRS structure as described with reference to FIGS. 1-4.

Similarly, according to one or more embodiments of the present disclosure, method 600 receives an uplink DMRS trigger from a base station to enable transmission of the uplink DMRS in the uplink TTI of the uplink subframe. Steps to be performed (not shown) may be further included. Uplink DMRS triggers may be carried in the downlink TTI of the downlink subframe that supports two or more downlink TTIs. As an example, the uplink DMRS trigger may be one or more bits to allow transmission and / or configuration of the corresponding DMRS. According to one or more embodiments of the present disclosure, the uplink DMRS trigger may include information on how to configure the uplink DMRS transmitted from the user equipment to the base station. As described with reference to FIGS. 2-4, some types of DMRS configuration information may be included in the trigger. As an example, the trigger may indicate in the uplink TTI which candidate symbol position the uplink DMRS occupies. The user device may trigger the transmission of the uplink DMRS according to the setting information indicated in the received trigger.

According to one or more additions or alternatives of the present disclosure, the uplink DMRS may be periodically received from the user equipment. The uplink DMRS is controlled to be transmitted in a periodic manner, for example, by higher layer signaling.

7A-7C schematically show exemplary UL and DL subframes with uplink DMRS according to one or more embodiments of the present disclosure to which uplink DMRS is transmitted during the uplink data scheduling process. It is a figure.

During the uplink data scheduling process, the base station may transmit the uplink DMRS to the user equipment by including it in the DCI for uplink data scheduling (ie, UL grant). As an example, one or more bits may be added to the existing DCI format 0 and / or format 4 to represent the uplink DMRS trigger. In that case, the downlink TTI is configured to schedule both the uplink data (PUSCH) and the triggered uplink DMRS.

As shown in FIG. 7A, the base station transmits DCI for uplink data scheduling (ie, UL grant) in DL TTI_n. In response, the user device transmits an uplink data transmission (ie, PUSCH) at UL TTI_n + k. Here, k is an integer, which may normally be set to 4 in the FDD system and may be predefined in the TDD system according to the uplink / downlink configuration. When detecting the uplink DMRS trigger included in the DCI received in DL TTI_n, the user apparatus may transmit the uplink DMRS in UL TTI_n + k according to the DMRS setting information included in the trigger. Thus, the uplink DMRS and PUSCH share the same UL TTI_n + k. As described in FIGS. 2-4, the uplink DMRS and uplink data may be multiplexed in the frequency domain and / or the uplink DMRS may occupy the M symbol of UL TTI_n + k, UL. The remaining symbols of TTI_n + k may be used to transmit scheduled uplink data. As a result, the PUSCH of UL TTI_n + k may be shortened to occupy the (LM) symbol. Alternatively, PUSCH and DMRS may be staggered in the frequency domain, as shown in FIG. 4A or 4B.

If the channel state changes slightly, the base station may decide not to trigger the transmission of the uplink DMRS, and the channel state estimate can be obtained based on the previous DMRS. For example, in DL TTI_n + 1 and DL TTI_n + 2, DCI does not include a trigger. Therefore, the user device transmits the uplink data scheduled in UL TTI_n + k + 1, UL TTI_n + k + 2, where UL DMRS is not transmitted.

FIG. 7B shows another example for dealing with a situation where a base station schedules uplink data and triggers uplink DMRS in the same DL TTI. In this example, the uplink DMRS may be configured to be pre-transmitted. As shown in FIG. 7B, when receiving an uplink DMRS trigger with DCI at DL TTI_n, it may be predefined that the user device can transmit the DMRS triggered at UL TTI_n + k-1. Then, at UL TTI_n + k, the user device transmits the uplink data scheduled by DCI. Here, n represents the TTI number of the downlink TTI to which the downlink control information for uplink data scheduling is transmitted, and k is a predetermined integer representing a predefined number of TTIs for scheduling. be.

FIG. 7C shows yet another example for dealing with a situation where a base station schedules uplink data and triggers uplink DMRS in the same DL TTI. In this example, the transmission of the scheduled uplink data may be delayed by 1 TTI after the uplink DMRS has been transmitted. As shown in FIG. 7C, when receiving an uplink DMRS trigger with a DCI of DL TTI_n, it may be predefined that the user device can transmit the DMRS triggered at UL TTI_n + k. Then, at UL TTI_n + k + 1, the user device transmits the uplink data scheduled by DCI. Here, n represents the TTI number of the downlink TTI to which the downlink control information for uplink data scheduling is transmitted, and k is a predetermined integer representing a predefined number of TTIs for scheduling. be. In those TTIs without DMRS transmission, the base station may demodulate the received PUSCH with reference to the previously received uplink DMRS.

Here, one of ordinary skill in the art will solve the problem caused by the collision between the transmission of the uplink DMRS and the uplink data (eg, PUSCH), as described with reference to FIGS. 7A-7C. Therefore, it should be understood that periodic uplink DMRS may also be applied to these embodiments, which are set semi-statically by higher layer signaling.

In some embodiments, the uplink DMRS trigger may be received separately from the DCI for uplink data scheduling. That is, the uplink DMRS triggers may be sent separately in a TTI without a DCI for uplink scheduling.

FIG. 8 is a diagram schematically showing an exemplary UL and DL subframe with uplink DMRS according to a further embodiment of the present disclosure, in which the uplink DMRS trigger is transmitted separately at DL TTI_n. As shown in FIG. 8, in such an embodiment, the triggered uplink DMRS does not collide with the scheduled uplink data. For example, depending on the trigger received at DL TTI_n, the user device may transmit the UL TTI_n + k uplink DMRS. Then, in response to the DCI for uplink data scheduling received at DL TTI_n + 1, the user apparatus may transmit the uplink data scheduled at UL TTI_n + k + 1.

In an implementation, if the user equipment requires PUSCH transmission, the base station may trigger the uplink DMRS by transmitting an uplink DMRS trigger in a separate TTI after the schedule request. The uplink DMRS trigger may include a resource allocation area. After the DMRS trigger, the base station transmits a compact DCI for uplink data scheduling because the user equipment can reference the resource allocation area of the uplink DMRS trigger to perform subsequent uplink data transmission. This allows the PUSCH to be scheduled.

During the downlink data scheduling process, the uplink DMRS may be required to demodulate the uplink control channel (eg, PUCCH). Therefore, according to one or more embodiments of the present disclosure, the base station may transmit the uplink DMRS to the user apparatus as needed to trigger the transmission of the uplink DMRS. Additional or alternative, the uplink DMRS may be controlled to be transmitted in a cyclical manner, eg, by upper layer signaling, to meet the requirements for PUCCH demodulation.

FIG. 9 is a diagram schematically showing an exemplary method for demodulating a PUCCH channel based on an uplink DMRS according to one or more embodiments of the present disclosure. As shown in FIG. 9, the uplink DMRS is transmitted independently of the PUCCH. For example, the uplink DMRS and PUCCH (including CQI / PMI / RI) cycles and / or offsets may be different. In another example, the uplink DMRS is aperiodic, as it may be triggered by the base station, for example in DCI information.

Since the PUCCH is transformed in the same way as the uplink DMRS or modulated with the same ZC sequence, after demodulating the PUCCH information, the remaining sequence can be used as a demodulation reference signal for channel estimation. Provides a reference to the next subsequent PUCCH and / or uplink data. That is, the physical uplink control channel may be demodulated based on the uplink DMRS. Then, one or more subsequent physical uplink control channels may be demodulated based on previously received uplink DMRS and / or demodulated physical uplink control channels.

10A-10C schematically show exemplary UL and DL subframes with uplink DMRS according to one or more embodiments of the present disclosure in which the uplink DMRS is transmitted during the downlink data scheduling process. It is a figure.

In the downlink data scheduling process, the user equipment needs to transmit the ACK / NACK feedback information to the base station on the PUCCH. Since the ACK / NACK feedback information is related to downlink data scheduling, both the user equipment and the base station know to which UL TTI the ACK / NACK feedback information is transmitted. If the base station requires uplink DMRS from the user equipment to demodulate the ACK / NACK feedback information, the base station may trigger the transmission of uplink DMRS by transmitting a downlink DMRS trigger. Alternatively, periodic uplink DMRS may be configured by semi-static radio resource control (RRC) signaling.

According to one or more embodiments of the present disclosure, the transmission of the uplink DMRS may be triggered by an uplink DMRS trigger. The base station may transmit an uplink DMRS trigger with a DCI for downlink data scheduling (ie, DL scheduling) in the downlink TTI. Example As an example, one or more bits may be added to an existing DCI for downlink data scheduling to represent an uplink DMRS trigger. In that case, the downlink TTI is configured to schedule both the downlink data (PDSCH) and the triggered uplink DMRS.

As shown in FIG. 10A, the base station transmits a DCI for downlink data scheduling (ie, DL grant) at DL TTI_n. In response, the user device sends ACK / NACK feedback for downlink data scheduling (in PUCCH) at UL TTI_n + k. Here, k is an integer and may be normally set as 4 in the FDD system or may be predefined in the TDD system according to the uplink / downlink configuration. When detecting the uplink DMRS trigger included in the DCI received by DL TTI_n, the user apparatus may transmit the uplink DMRS in UL TTI_n + k according to the DMRS setting information included in the trigger. Thus, the uplink DMRS and ACK / NACK feedback information share the same UL TTI_n + k. As described in FIGS. 2-4, the uplink DMRS and ACK / NACK feedback information may be multiplexed in the frequency domain and / or the uplink DMRS occupy the M symbol of UL TTI_n + k and UL TTI_n + k. The remaining symbols of are used to transmit ACK / NACK feedback information. As a result, in UL TTI_n + k PUCCH may be shortened to occupy the (LM) symbol. Alternatively, PUCCH and DMRS may be staggered in the frequency domain, as shown in FIG. 4A or 4B.

If it is not necessary to estimate the channel state, the base station may decide not to trigger the transmission of the uplink DMRS. For example, in DL TTI_n + 1, DL TTI_n + 2, the trigger is not included in DCI. Therefore, the user apparatus transmits ACK / NACK feedback information scheduled in UL TTI_n + k + 1, UL TTI_n + k + 2, where UL DMRS is not transmitted. In these TTIs without DMRS transmission, the base station may demodulate the received ACK / NACK feedback information with reference to the previously received uplink DMRS.

FIG. 10B shows another example for dealing with a situation where a base station schedules downlink data and triggers uplink DMRS in the same DL TTI. In this example, the uplink DMRS may be configured to be pre-transmitted. As shown in FIG. 10B, when receiving an uplink DMRS trigger with DCI for downlink scheduling at DL TTI_n, even if it is predefined that the user device can transmit the triggered DMRS at UL TTI_n + k-1. good. Then, in UL TTI_n + k, the user apparatus transmits ACK / NACK feedback information for downlink data scheduling. Here, n represents the TTI number of the downlink TTI to which the downlink control information for downlink data scheduling is transmitted, and k is a predetermined integer representing a predefined number of TTIs for scheduling. be.

FIG. 10C shows yet another example for dealing with a situation where a base station schedules downlink data and triggers uplink DMRS in the same DL TTI. In this example, the transmission of the corresponding ACK / NACK feedback information for the downlink data scheduling may be delayed by 1 TTI after the uplink DMRS has been transmitted. As shown in FIG. 10C, when receiving the uplink DMRS together with the downlink data in DL TTI_n, it may be defined in advance that the user device can first transmit the DMRS triggered in UL TTI_n + k. Then, at UL TTI_n + k + 1, the user device transmits ACK / NACK feedback information for the downlink data. Here, n represents the TTI number of the downlink TTI to which the downlink control information for downlink data scheduling is transmitted, and k is a predetermined integer representing a predefined number of TTIs for scheduling. ..

Here, in order to solve the problem caused by the collision between the transmission of the uplink DMRS and the ACK / NACK feedback information (that is, PUCCH), the same method as described with reference to FIGS. Those skilled in the art should understand that a typical uplink DMRS may be applied to these embodiments that are semi-statically configured by higher layer signaling.

According to other embodiments of the present disclosure, the uplink DMRS trigger does not have to be carried in the DCI for downlink data scheduling. The base station may use a separate DL TTI to transmit the uplink DMRS trigger. In such an embodiment, the triggered uplink DMRS may not conflict with the ACK / NACK feedback information for downlink data scheduling. For example, in response to a trigger received at DL TTI_n, the user device may transmit an uplink DMRS at UL TTI_n + k. Then, in response to the downlink data received at DL TTI_n + 1, the user apparatus may transmit the uplink data scheduled at UL TTI_n + k + 1.

FIG. 11 is a diagram schematically showing a method 1100 for communication by a base station according to one or more embodiments of the present disclosure in the case of downlink. Method 1100 of FIG. 11 describes a process of downlink DMRS transmission from the perspective of a base station. As shown in FIG. 11, in step S1110, the base station transmits the downlink DMRS to the user apparatus in the downlink TTI of the downlink subframe. The downlink subframe supports two or more downlink TTIs.

FIG. 12 is a diagram schematically showing a method for communication by a user device according to one or more embodiments of the present disclosure. Method 1200 of FIG. 12 describes the process of downlink DMRS transmission from the point of view of the user equipment. As shown in FIG. 12, in step S1210, the user apparatus base station the uplink demodulation reference signal (DMRS) at the uplink TTI of the uplink subframe that supports two or more uplink transmission time intervals (TTIs). Receive from.

The transmission of the downlink DMRS is controlled independently of the transmission of the downlink physical channel (eg, PDSCH, etc.). Thus, some downlink TTIs supported by the downlink subframe may be configured to transmit only the downlink control information and / or the downlink data without the downlink DMRS. It will be possible. The downlink DMRS may employ any suitable DMRS structure as described with reference to FIGS. 1-4.

According to one or more embodiments of the present disclosure, the downlink DMRS trigger for enabling transmission of the downlink DMRS may be transmitted from the base station to the user equipment. As an example, the downlink DMRS trigger may be one or more bits to allow transmission and / or configuration of the corresponding DMRS. As described with reference to FIGS. 2-4, some types of DMRS configuration information may be included in the trigger. As an example, a downlink DMRS trigger may include, but is not limited to, information indicating at least one of the following items: the number of symbols occupied by the downlink DMRS; the time of the triggered downlink DMRS; the downlink DMRS. Resource allocation; and candidate symbol positions occupied by the downlink DMRS in the downlink TTI.

13A-13B are diagrams schematically illustrating exemplary UL and DL subframes with downlink DMRS according to one further embodiment of the present disclosure in which downlink DMRS is enabled by a downlink DMRS trigger. be.

According to one or more embodiments of the present disclosure, a downlink DMRS trigger for enabling transmission of a downlink DMRS may be transmitted in the same downlink TTI with a DCI for downlink data scheduling. good. As shown in FIG. 13A, in DL TTI_n, the user equipment may transmit the downlink DMRS to the user equipment by including the downlink DMRS in the DCI for downlink data scheduling. In some implementations, at least a portion of the downlink DMRS may be sparse-multiplexed with the downlink data in the downlink TTI of the downlink subframe. Additional or alternative, the downlink DMRS may occupy one or more symbols of the downlink TTI, and the remaining symbols may be used for downlink data transmission. At the next downlink TTI_n + 1, the base station does not trigger the transmission of the downlink DMRS because the user equipment can demodulate the downlink data transmitted at downlink TTI_n + 1 based on the previously received downlink DMRS. You may decide that.

According to additional or alternative embodiments, the downlink DMRS trigger to allow transmission of the downlink DMRS may be transmitted separately from the DCI for downlink data scheduling. As shown in FIG. 13B, in the downlink TTI_n, the DMRS trigger is transmitted in order to indicate the downlink DMRS setting information to the user apparatus. At the same TTI_n, the base station transmits the downlink DMRS according to the setting information included in the downlink DMRS trigger. According to some implementations, the user equipment may refer to the resource allocation area of the downlink DMRS trigger to perform subsequent downlink data transmissions, so consider the resource allocation information contained in the downlink DMRS trigger. The base station may then schedule the PDSCH in at least one subsequent TTI by transmitting a compact DCI for downlink data scheduling.

To communicate the downlink DMRS independently of scheduling the physical downlink data channel (eg, PDSCH), according to one or more additional or alternative embodiments of the present disclosure, the downlink The DMRS may be periodically transmitted from the base station to the user equipment. The downlink DMRS may be controlled to be transmitted in a periodic manner, for example, by higher layer signaling.

FIG. 14 is a block diagram schematically showing a base station according to one or more embodiments of the present disclosure.

As shown in FIG. 14, base station 1400 is configured to communicate with one or more user devices based on downlink and uplink subframe structures with short TTIs. The base station 1400 includes a transmitting unit 1410 and a receiving unit 1420. Base station 600 also selectively transmits one or more antennas (not shown in FIG. 14) used to transmit signals to one or more user devices and receive signals from one or more user devices. A suitable radio frequency transceiver (not shown in FIG. 14) that can be coupled may be provided.

Base station 1400 includes a processor 141 that may include one or more microprocessors or microprocessors, as well as other digital hardware, which may include a digital signal processor (DSP), dedicated digital logic, and the like. .. The processor 141 is a memory that may include one or more types of memory such as read-only memory (ROM), random access memory, cache memory, flash memory device, optical storage device, etc. (not shown in FIG. 14). It may be configured to execute the program code stored in. The program code stored in the memory performs one or more program instructions for executing one or more telecommunications and / or data communication protocols, and one or more techniques described herein in some embodiments. Includes instructions to do. In some implementations, processor 141 may be used to cause transmitter 1410 and receiver 1420 to perform the corresponding functions according to one or more embodiments of the present disclosure.

According to an embodiment of one aspect of the present disclosure, the receiver 1420 is configured to receive the uplink DMRS from the user device in the uplink TTI of the uplink subframe supporting two or more uplink TTIs. NS. At least one uplink TTI supported by the uplink subframe is configured to transmit only the uplink control information and / or the uplink data without the uplink DMRS.

According to one or more embodiments of this aspect of the present disclosure, the transmitter 1510 transmits an uplink DMRS trigger to the user apparatus to enable transmission of the uplink DMRS in the uplink TTI of the uplink subframe. It may be configured to do so. Uplink DMRS triggers may be carried in the downlink TTI of the downlink subframe that supports two or more downlink TTIs. In some embodiments, the uplink DMRS trigger may include information indicating at least one of the following items: the number of symbols occupied by the uplink DMRS; the time of the triggered uplink DMRS; for the uplink DMRS. Resource allocation; and candidate symbol positions occupied by the uplink DMRS in the uplink TTI.

According to one or more embodiments of this aspect of the present disclosure, the uplink DMRS trigger may be included in the downlink control information for uplink data scheduling. Alternatively, the uplink DMRS trigger may be received separately from the downlink control information for uplink data scheduling.

According to one or more embodiments of this aspect of the present disclosure, the uplink DMRS may be received periodically from the user equipment.

In some embodiments of this aspect of the present disclosure, the receiver 1420 may be further configured to receive the uplink data scheduled at the uplink TTI n + k where the uplink DMRS is received; The uplink DMRS may be further configured to receive the uplink data scheduled at the uplink TTI n + k immediately following the uplink TTI n + k-1 on which the uplink DMRS is received; or the uplink on which the uplink DMRS is received. It may be further configured to receive the uplink data scheduled at the uplink TTI n + k + 1 immediately following TTI n + k. Here, n represents the TTI number of the downlink TTI to which the downlink control information for uplink data scheduling is transmitted, and k represents a predefined number of TTIs for uplink scheduling.

According to one or more embodiments of this aspect of the present disclosure, the physical uplink control channel may be demodulated based on the uplink DMRS. In some embodiments, additional physical uplink control channels may be demodulated based on the uplink DMRS and / or demodulated physical uplink control information.

According to one or more embodiments of this aspect of the present disclosure, the transmitter 1410 may be configured to transmit an uplink DMRS trigger included in the downlink control information for downlink data scheduling.

According to one or more embodiments of this aspect of the present disclosure, the receiver 1420 acknowledges / does not acknowledge downlink data scheduling at uplink TTI n + k where the uplink DMRS is received. NACK: non-acknowledgement) It may be further configured to receive feedback information; or ACK / for uplink data scheduling at uplink TTI n + k immediately after uplink TTI n + k-1 where uplink DMRS is received. It may be further configured to receive NACK feedback information; or to receive ACK / NACK feedback information for downlink data scheduling at uplink TTI n + k + 1 immediately after uplink TTI n + k where uplink DMRS is received. May be further configured. Here, n represents the TTI number of the downlink TTI to which the downlink data for downlink data scheduling is transmitted, and k represents the predefined number of TTIs for downlink scheduling.

According to one or more embodiments of this aspect of the present disclosure, the transmitter 1410 may be configured to transmit an uplink DMRS trigger separately from the downlink control information for downlink data scheduling. ..

According to an embodiment of another aspect of the present disclosure, the transmitter 1410 is configured to transmit a downlink DMRS to a user apparatus in a downlink TTI of a downlink subframe that supports two or more downlink TTIs. May be done. At least one downlink TTI supported by the downlink subframe is configured to transmit only the downlink control information and / or the downlink data without the downlink DMRS.

According to an embodiment of this aspect of the present disclosure, the transmitter 1410 is configured to transmit a downlink DMRS trigger to enable transmission of the downlink DMRS contained in the downlink control information for downlink data scheduling. It may be configured in. In some embodiments, the transmitter 1410 is further configured to transmit at least a portion of the downlink DMRS that is sparse-multiplexed with the downlink data in the downlink TTI of the downlink subframe. You may.

According to an alternative embodiment of this aspect of the present disclosure, the transmitter 1410 is a downlink DMRS to allow transmission of the downlink DMRS separately from the downlink control information for downlink data scheduling. It may be configured to send a trigger.

According to an embodiment of this aspect of the present disclosure, the downlink DMRS trigger may include information indicating at least one of the following items: the number of symbols occupied by the downlink DMRS; the time of the triggered downlink DMRS; Resource allocation for downlink DMRS; and candidate symbol positions occupied by downlink DMRS in uplink TTI.

According to an embodiment of this aspect of the present disclosure, the transmission unit 1410 may be configured to periodically transmit the downlink DMRS to the user equipment.

FIG. 15 is a block diagram schematically showing a user device according to one or more embodiments of the present disclosure.

As shown in FIG. 15, the user apparatus 1500 is configured to communicate with a base station based on a downlink and uplink subframe structure having a short TTI. The user device 1500 includes a receiving unit 1510 and a transmitting unit 1520. The user device 1500 also has one or more antennas (not shown in FIG. 15) used to transmit signals to other radio nodes such as NodeB, eNodeB or WiFi AP and receive signals from other nodes. A plurality of suitable radio frequency transceivers (not shown in FIG. 15) that can be operably coupled may be provided.

The user apparatus 1500 includes a processor 151 that may include one or more microprocessors or microcontrollers, as well as other digital hardware, which may include a digital signal processor (DSP), dedicated digital logic, and the like. The processor 151 is stored in a memory (not shown in FIG. 15) that may include one or several types of memory such as read-only memory (ROM), random access memory, cache memory, flash memory device, optical storage device, and the like. It may be configured to execute program code. The program code stored in the memory performs one or more program instructions for executing one or more telecommunications and / or data communication protocols, and, in some embodiments, one or more techniques described herein. Includes instructions to do. In some implementations, processor 151 may be used to cause receiver 1510 and transmitter 1520 to perform the corresponding functions according to one or more embodiments of the present disclosure.

According to an embodiment of one aspect of the present disclosure, the transmitter 1420 is configured to transmit the uplink DMRS to the base station in the uplink TTI of the uplink subframe supporting two or more uplink TTIs. NS. At least one uplink TTI supported by the uplink subframe is configured to transmit only the uplink control information and / or the uplink data without the uplink DMRS.

According to an embodiment of this aspect of the present disclosure, the receiver 1500 receives an uplink DMRS trigger from the base station to enable transmission of the uplink DMRS in the uplink TTI of the uplink subframe. It is composed. Uplink DMRS triggers may be carried in the downlink TTI of the downlink subframe that supports two or more downlink TTIs. According to some embodiments, the uplink DMRS trigger may include information indicating at least one of the following items: the number of symbols occupied by the uplink DMRS; the time of the triggered uplink DMRS; the uplink DMRS. Resource allocation for; and candidate symbol positions occupied by the uplink DMRS in the uplink TTI.

According to an embodiment of this aspect of the present disclosure, the receiver 1510 may be configured to receive an uplink DMRS trigger included in the downlink control information for uplink data scheduling. In some alternative embodiments, the receiver 1510 may be configured to receive the uplink DMRS trigger separately from the downlink control information for uplink data scheduling.

According to an embodiment of this aspect of the present disclosure, the transmitter 1520 may be configured to periodically transmit the uplink DMRS to the base station.

In some embodiments of this aspect of the present disclosure, the transmitter 1520 may be further configured to transmit the uplink data scheduled at the uplink TTI n + k where the uplink DMRS is received; The uplink DMRS may be further configured to transmit the scheduled uplink data at the uplink TTI n + k immediately following the uplink TTI n + k-1 on which the uplink DMRS is received; or the uplink on which the uplink DMRS is received. In the uplink TTI n + k + 1 immediately after TTI n + k, it may be further configured to transmit the scheduled uplink data. Here, n represents the TTI number of the downlink TTI to which the downlink control information for uplink scheduling is transmitted, and k represents the predefined number of TTIs for uplink scheduling.

According to one or more embodiments of this aspect of the present disclosure, the user apparatus 1500 may be configured to demodulate the physical uplink control channel based on the uplink DMRS. In some embodiments, the user apparatus 1500 may be configured to demodulate additional physical uplink control channels based on the uplink DMRS and / or demodulated uplink control channels.

According to one or more embodiments of this aspect of the present disclosure, the receiver 1510 may be configured to receive an uplink DMRS trigger included in the downlink control information for downlink data scheduling.

According to one or more embodiments of this aspect of the present disclosure, the transmitter is further configured to transmit ACK / NACK feedback information for downlink data scheduling at uplink TTI n + k where the uplink DMRS is received. Alternatively, it may be further configured to send ACK / NACK feedback information for downlink data scheduling at uplink TTI n + k immediately after uplink TTI n + k-1 where the uplink DMRS is received; , The uplink TTI n + k + 1 immediately after the uplink TTI n + k at which the uplink DMRS is received may be further configured to transmit ACK / NACK feedback information for the downlink data scheduling. Here, n represents the TTI number of the downlink TTI to which the downlink data for downlink data scheduling is transmitted, and k represents the predefined number of TTIs for downlink scheduling.

According to one or more embodiments of this aspect of the present disclosure, the receiver 1510 may be configured to receive an uplink DMRS trigger separately from the downlink control information for downlink data scheduling. ..

According to an embodiment of another aspect of the present disclosure, the receiver 1510 is configured to receive a downlink DMRS from a base station in a downlink TTI of a downlink subframe that supports two or more downlink TTIs. NS. At least one downlink TTI after the downlink TTI for which the downlink DMRS is received is configured not to transmit any downlink DMRS.

According to an embodiment of this aspect of the present disclosure, the receiver 1510 is configured to receive a downlink DMRS trigger to enable transmission of the downlink DMRS contained in the downlink control information for downlink data scheduling. It may be configured in. In some embodiments, the receiver 1510 is configured to receive at least a portion of the downlink DMRS that is sparse-multiplexed with the downlink data in the downlink TTI of the downlink subframe. You may.

According to an embodiment of this aspect of the present disclosure, the receiver 1510 receives a downlink DMRS trigger to enable transmission of the downlink DMRS separately from the downlink control information for downlink data scheduling. It may be configured as follows.

According to an embodiment of this aspect of the present disclosure, the downlink DMRS trigger may include information indicating at least one of the following items: the number of symbols occupied by the downlink DMRS; the time of the triggered downlink DMRS; Resource allocation for downlink DMRS; and candidate symbol positions where downlink DMRS is occupied in the uplink TTI.

According to an embodiment of this aspect of the present disclosure, the receiver 1510 may be configured to periodically receive the downlink DMRS from the base station.

In general, various exemplary embodiments may be implemented in hardware or dedicated circuits, software, logical, or any combination thereof. The present disclosure is not limited to this, for example, some embodiments may be implemented in hardware and other embodiments may be implemented in firmware or software that may be executed by a controller, microprocessor or other computing device. It is also good. Various aspects of the exemplary embodiments of the present disclosure are illustrated and described as block diagrams and signaling diagrams, but these blocks, devices, systems, techniques or methods described in the present disclosure are limited. It is well understood that it can be implemented by hardware, software, firmware, dedicated circuits or logicals, general purpose hardware or controllers or other computing devices, or some combination thereof, as examples that are not.

As such, it should be understood that at least some aspects of the exemplary embodiments of the present disclosure may be implemented by various components such as integrated circuit chips and modules. As is well known in the art, integrated circuit design is largely a highly automated process by a highly automated process.

The disclosure may also be embodied in a computer program product that includes all features capable of implementing the methods described herein, and the methods may be implemented when loaded into a computer system.

The present disclosure has been specifically illustrated and described with reference to preferred embodiments. It should be understood by those skilled in the art that various changes in form and detail can be made without departing from the spirit and scope of the present disclosure.

Claims (16)

It is a method by the user device,
The first information is received from the base station by signaling in the upper layer,
Second information is received from the base station by DCI (Downlink Control Information), and the second information is received.
In addition to the first DMRS (Demodulation Reference Signal) for PDSCH (Physical Downlink Sharp Channel), at least one second DMRS for PDSCH is a symbol at at least one second position in the scheduling unit. Whether or not to be mapped is determined based on the first information.
When the at least one second DMRS is mapped, the user apparatus is provided with a group of candidates for a second position within the scheduling unit by the first information.
The first DMRS is mapped to one symbol at the first position in the scheduling unit, regardless of the first information.
When the at least one second DMRS is mapped, the first DMRS and the at least one second DMRS are received and
The at least one second position is determined from within the group based on the second information.
If the at least one second DMRS is not mapped, the scheduling unit receives the first DMRS without receiving the at least one second DMRS.
Method. The method of claim 1, wherein the first position is symbol 0 or symbol 3. The method of claim 1 or 2, further comprising receiving a third piece of information indicating the first position. The method according to any one of claims 1 to 3, wherein the first position is located in the scheduling unit in the time domain before all the at least one second position. In the first position or at least one second position, the first DMRS or at least one second DMRS is mapped to one in every resource element in the frequency domain.
The remaining resource elements that are not used by the first DMRS or the second DMRS in the first position or at least one second position are used to receive the PDSCH.
The method according to any one of claims 1 to 4. The method according to any one of claims 1 to 4, wherein the PDSCH is not received at the time length in the first position or at least one second position. The method according to any one of claims 1 to 6, wherein the first position or at least one second position is located in the scheduling unit in the time domain and prior to the PDSCH resource. The method according to any one of claims 1 to 7, wherein it is determined based on the first information whether or not the at least one second position has more symbols than the first position. .. It ’s a base station method,
The first information is transmitted to the user device by signaling in the upper layer, and the first information is transmitted.
Second information is transmitted to the user device by DCI (Downlink Control Information), and the second information is transmitted.
In addition to the first DMRS (Demodulation Reference Signal) for PDSCH (Physical Downlink Sharp Channel), at least one second DMRS for PDSCH with symbols at at least one second position in the scheduling unit. Whether or not to transmit depends on the first information, and it depends on the first information.
When the at least one second DMRS is mapped, the first information provides a group of candidates for a second position within the scheduling unit.
The first DMRS is transmitted with one symbol at the first position in the scheduling unit, regardless of the first information.
When the at least one second DMRS is transmitted, the first DMRS and the at least one second DMRS are transmitted, and the first DMRS and the at least one second DMRS are transmitted.
The at least one second position is determined from within the group based on the second information.
When the at least one second DMRS is not transmitted, the scheduling unit transmits the first DMRS without transmitting the at least one second DMRS.
Method. The method of claim 9, wherein the first position is symbol 0 or symbol 3. The method of claim 9 or 10, further comprising transmitting a third piece of information indicating the first position. The method of any of claims 9-11, wherein the first position is located in the scheduling unit in the time domain prior to all at least one second position. In the first position or at least one second position, the first DMRS or at least one second DMRS is mapped to one in every resource element in the frequency domain.
The remaining resource elements that are not used by the first DMRS or the second DMRS in the first position or at least one second position are used to transmit the PDSCH.
The method according to any one of claims 9 to 12. The method of any of claims 9-12, wherein no PDSCH is transmitted at the time length in the first position or at least one second position. The method of any of claims 9-14, wherein the first position or at least one second position is located in the scheduling unit in the time domain and prior to the PDSCH resource. The method according to any one of claims 9 to 15, which determines whether or not the at least one second position has more symbols than the first position based on the first information. ..

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