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EP-3780777-B1 - USER TERMINAL APPARATUS, RADIO COMMUNICATION METHOD AND BASE STATION

EP3780777B1EP 3780777 B1EP3780777 B1EP 3780777B1EP-3780777-B1

Inventors

  • MATSUMURA, YUKI
  • TAKEDA, KAZUKI
  • NAGATA, SATOSHI

Dates

Publication Date
20260513
Application Date
20180406

Claims (5)

  1. A terminal (20) comprising: a control section (401) configured to determine a power for a demodulation reference signal, DMRS, for a physical shared channel without taking account of any resource element, RE, to which the DMRS is not allocated, according to a ratio of energy per resource element, EPRE, of the physical shared channel to an EPRE for the DMRS to which the number of code division multiplexing, CDM, groups without data is applied; and a transmitting/receiving section (203) configured to perform at least one of transmission and reception of the DMRS based on the power for the DMRS, wherein when the number of DMRS CDM groups without data equals to one in DMRS configuration type 1, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are used for transmitting data equals to one, or wherein when the number of DMRS CDM groups without data equals to two in DMRS configuration type 1, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are not used for transmitting data equals to one, or wherein when the number of DMRS CDM groups without data equals to one in DMRS configuration type 2, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are used for transmitting data equals to two, or wherein when the number of DMRS CDM groups without data equals to two in DMRS configuration type 2, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are not used for transmitting data equals to one and the number of CDM groups for which the corresponding resource elements are used for transmitting data equals to one, or wherein when the number of DMRS CDM groups without data equals to three in DMRS configuration type 2, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are not used for transmitting data equals to two.
  2. The terminal (20) according to claim 1, wherein the control section (401) is configured to determine the power for the DMRS without taking account of any RE to which the DMRS is not allocated, according to a table providing a definition of the ratio.
  3. A radio communication method for a terminal (20) comprising: determining a power for a demodulation reference signal, DMRS, for a physical shared channel without taking account of any resource element, RE, to which the DMRS is not allocated, according to a ratio of energy per resource element, EPRE, of the physical shared channel to an EPRE for the DMRS to which the number of code division multiplexing, CDM, groups without data is applied; and performing at least one of transmission and reception of the DMRS based on the power for the DMRS, wherein when the number of DMRS CDM groups without data equals to one with DMRS configuration type 1, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are used for transmitting data equals to one, or wherein when the number of DMRS CDM groups without data equals to two in DMRS configuration type 1, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are not used for transmitting data equals to one, or wherein when the number of DMRS CDM groups without data equals to one in DMRS configuration type 2, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are used for transmitting data equals to two, or wherein when the number of DMRS CDM groups without data equals to two in DMRS configuration type 2, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are not used for transmitting data equals to one and the number of CDM groups for which the corresponding resource elements are used for transmitting data equals to one, or wherein when the number of DMRS CDM groups without data equals to three in DMRS configuration type 2, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are not used for transmitting data equals to two.
  4. A base station (10) comprising: a control section (301) configured to determine a power for a demodulation reference signal, DMRS, for a physical shared channel without taking account of any resource element, RE, to which the DMRS is not allocated, according to a ratio of energy per resource element, EPRE, of the physical shared channel to an EPRE for the DMRS to which the number of code division multiplexing, CDM, groups without data is applied; and a transmitting/receiving section (103) configured to perform at least one of transmission and reception of the DMRS based on the power for the DMRS, wherein when the number of DMRS CDM groups without data equals to one with DMRS configuration type 1, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are used for transmitting data equals to one, or wherein when the number of DMRS CDM groups without data equals to two in DMRS configuration type 1, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are not used for transmitting data equals to one, or wherein when the number of DMRS CDM groups without data equals to one in DMRS configuration type 2, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are used for transmitting data equals to two, or wherein when the number of DMRS CDM groups without data equals to two in DMRS configuration type 2, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are not used for transmitting data equals to one and the number of CDM groups for which the corresponding resource elements are used for transmitting data equals to one, or wherein when the number of DMRS CDM groups without data equals to three in DMRS configuration type 2, the number of DMRS CDM groups equals to one and the number of CDM groups for which the corresponding resource elements are not used for transmitting data equals to two.
  5. A system comprising the terminal according to any one of claims 1 to 2 and the base station according to claim 4.

Description

Technical Field The present disclosure relates to a user terminal in next-generation mobile communication systems. Background Art In the UMTS (Universal Mobile Telecommunications System) network, the specifications of Long Term Evolution (LTE) have been drafted for the purpose of further increasing high speed data rates, providing lower latency, and so on (see Non-Patent Literature 1). For the purpose of further high capacity, advancement of LTE (LTE Rel. 8, Rel. 9), and so on, the specifications of LTE-A (LTE-Advanced, LTE Rel. 10, Rel. 11, Rel. 12, Rel. 13) have been drafted. Successor systems of LTE (referred to as, for example, "FRA (Future Radio Access)," "5G (5th generation mobile communication system)," "5G+ (plus)," "NR (New Radio)," "NX (New radio access)," "FX (Future generation radio access)," "LTE Rel. 14," "LTE Rel. 15" (or later versions), and so on) are also under study. For transmission of an uplink shared channel (PUSCH (Physical Uplink Shared Channel)) in existing LTE systems (for example, LTE Rel. 8 to Rel. 13), a decoding reference signal (DMRS) for the channel is transmitted in all the resource elements in the same transmission bandwidth as that of the PUSCH. OPPO: "Remaining issues on DMRS", 3GPP DRAFT; R1-1802099, vol. RAN WG1, no. Athens, Greece; 15 February 2018 discusses a UE DM-RS transmission procedure where a ratio of PUSCH EPRE to DM-RS EPRE is given by a table according to a number of DM-RS CDM groups without data as signaled by DCI.NOKIA ET AL.: "On remaining issues of DM-RS for NR physical data channels", 3GPP DRAFT; R1-1800756, vol. RAN WG1, no. Vancouver, Canada; 13 January, 2018, discusses power allocation for downlink where a ratio of NR PDSCH EPRE to DM-RS EPRE and a DMRS scaling factor are given by a table according to the number of DM-RS CDM groups without data. Citation List Non-Patent Literature Non-Patent Literature 1: 3GPP TS 36.300 V8.12.0 "Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 8)," April, 2010 Summary of Invention Technical Problem In future radio communication systems (for example, NR), a DMRS mapped to a downlink shared channel (PDSCH (Physical Downlink Shared Channel)) and a PUSCH is sometimes in a comb-like (comb-tooth-like) configuration in a frequency direction. One side of this comb is for the DMRS, and the other side is set to null. In a null resource, nothing may be transmitted, or data may be transmitted. However, in NR, the same transmission power may not be used for symbols of data and DMRS symbols of the data according to currently studied specifications about DMRS power, and this may cause negative effects such as interference and reduction in throughput. In view of the above, an object of the present disclosure is to provide a user terminal capable of using the same transmission power for data symbols and DMRS symbols even in NR. Solution to Problem The mentioned problems are solved by the subject-matter of the independent claims. Further preferred embodiments are defined in the dependent claims. A user terminal according to one aspect includes a transmitting/receiving section that performs at least one of transmission and reception of a demodulation reference signal (DMRS) for a physical shared channel, and a control section that determines a power for the DMRS without taking account of a resource element to which the DMRS is not allocated, with reference to a table providing a definition of a ratio of a power (EPRE) for each resource element of the physical shared channel to an EPRE for the DMRS to which a certain number of CDM groups is applied. Advantageous Effects of Invention According to an aspect of the present disclosure, it is possible to use the same transmission power for data symbols and DMRS symbols even in NR. Brief Description of Drawings FIG. 1 is a diagram to show an existing definition of a ratio of PDSCH EPRE to DMRS EPRE (1/βDMRS [dB]);FIG. 2 is a diagram to show an existing definition of the ratio of PUSCH EPRE to DMRS EPRE (1/βDMRS [dB]);FIG. 3 is a diagram to show an example of the ratio of PDSCH EPRE to DMRS EPRE (1/βDMRS [dB]);FIG. 4 is a diagram to show an example of the ratio of PUSCH EPRE to DMRS EPRE (1/βDMRS [dB]);FIG. 5 is a diagram to show an example of a schematic structure of a radio communication system according to one embodiment;FIG. 6 is a diagram to show an example of an overall structure of a radio base station according to one embodiment;FIG. 7 is a diagram to show an example of a functional structure of the radio base station according to one embodiment;FIG. 8 is a diagram to show an example of an overall structure of a user terminal according to one embodiment;FIG. 9 is a diagram to show an example of a functional structure of the user terminal according to one embodiment; andFIG. 10 is a diagram to show an example of a hardware structure of the radio base station and the user terminal ac