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EP-3280173-B1 - USER TERMINAL, WIRELESS COMMUNICATION SYSTEM, AND WIRELESS COMMUNICATION METHOD

EP3280173B1EP 3280173 B1EP3280173 B1EP 3280173B1EP-3280173-B1

Inventors

  • TAKEDA, KAZUKI
  • NAGATA, SATOSHI

Dates

Publication Date
20260506
Application Date
20160318

Claims (7)

  1. A user terminal (20) that can communicate with a radio base station by using six or more component carriers, the user terminal comprising: a receiving section (203) that receives scheduling information transmitted from the radio base station; a control section (401) that determines based on the scheduling information to apply spatial bundling of a transmission acknowledgement signal only to a component carrier that the spatial bundling is applicable to; and a transmission section (203) that transmits the transmission acknowledgement signal by using a PUCCH format 3, wherein, when a downlink shared channel is allocated to 10 or more component carriers based on the scheduling information, the control section applies the spatial bundling of the transmission acknowledgement signal only to the component carrier that the spatial bundling is applicable to, wherein the control section (401) dynamically determines whether or not the spatial bundling of the transmission acknowledgement signal is applicable to the component carrier that the spatial bundling is applicable to, according to the scheduling information of the component carrier that the spatial bundling is applicable to, wherein the scheduling information includes a downlink allocation index indicating how many component carriers are scheduled, and wherein the downlink allocation index is only included in the scheduling information of the component carrier that the spatial bundling is applicable to.
  2. The user terminal (20) according to claim 1, wherein the control section (401) controls generation of the bits for the transmission acknowledgement signal based on a number of cells that are configured in the terminal (20) by higher layer signaling.
  3. The user terminal (20) according to claim 1 or 2, wherein the control section (401) controls generation of the transmission acknowledgement signal bits based on a transmission mode of the downlink data signal.
  4. The user terminal (20) according to any one of claims 1 to 3, wherein at least one of frequency division duplex (FDD) and time division duplex (TDD) is applied to the plurality of cells.
  5. A radio communication method performed by a user terminal (20) that can communicate with a radio base station by using six or more component carriers, the radio communication method comprising: receiving scheduling information transmitted from the radio base station; determining based on the scheduling information to apply spatial bundling of a transmission acknowledgement signal only to a component carrier that the spatial bundling is applicable to; and transmitting the transmission acknowledgement signal by using a PUCCH format 3, wherein, when a downlink shared channel is allocated to 10 or more component carriers based on the scheduling information, the spatial bundling of the transmission acknowledgement signal is applied only to the component carrier that the spatial bundling is applicable to, wherein whether or not the spatial bundling of the transmission acknowledgement signal is applicable to the component carrier that the spatial bundling is applicable to, is dynamically determined according to the scheduling information of the component carrier that the spatial bundling is applicable to, wherein the scheduling information includes a downlink allocation index indicating how many component carriers are scheduled, and wherein the downlink allocation index is only included in the scheduling information of the component carrier that the spatial bundling is applicable to.
  6. A base station (10) that can perform communication by using six or more component carriers, the base station (10) comprising: a transmitting section (103) that transmits, to a user terminal (20), scheduling information for determining to apply spatial bundling of a transmission acknowledgement signal only to a component carrier that the spatial bundling is applicable to; and a receiving section (103) that receives the transmission acknowledgement signal by using a PUCCH format 3, wherein, when a downlink shared channel is allocated to 10 or more component carriers based on the scheduling information, the spatial bundling of the transmission acknowledgement signal is applied, by the user terminal (20), only to the component carrier that the spatial bundling is applicable to, wherein whether or not the spatial bundling of the transmission acknowledgement signal is applicable to the component carrier that the spatial bundling is applicable to, is dynamically determined by the user terminal (20) according to the scheduling information of the component carrier that the spatial bundling is applicable to, wherein the scheduling information includes a downlink allocation index indicating how many component carriers are scheduled, and wherein the downlink allocation index is only included in the scheduling information of the component carrier that the spatial bundling is applicable to.
  7. A radio communication system (1) comprising: a radio base station (10) and a user terminal (20) that perform communication by using six or more component carriers; and wherein the user terminal (20) includes a receiving section (203) that receives scheduling information transmitted from the radio base station, a control section (401) that determines based on the scheduling information to apply spatial bundling of a transmission acknowledgement signal only to a component carrier that the spatial bundling is applicable to, and a transmission section (203) that transmits the transmission acknowledgement signal by using a PUCCH format 3, wherein, when a downlink shared channel is allocated to 10 or more component carriers based on the scheduling information, the control section applies the spatial bundling of the transmission acknowledgement signal only to the component carrier that the spatial bundling is applicable to, wherein the control section (401) dynamically determines whether or not the spatial bundling of the transmission acknowledgement signal is applicable to the component carrier that the spatial bundling is applicable to, according to the scheduling information of the component carrier that the spatial bundling is applicable to, wherein the scheduling information includes a downlink allocation index indicating how many component carriers are scheduled, and wherein the downlink allocation index is only included in the scheduling information of the component carrier that the spatial bundling is applicable to, and wherein the base station (10) includes a transmitting section (103) that transmits, to the user terminal (20), the scheduling information; and a receiving section (103) that receives the transmission acknowledgement signal.

Description

Technical Field The present invention relates to a user terminal, a radio communication system, and a radio communication method of the next-generation communication system. Background Art In UMTS (Universal Mobile Telecommunications System) networks, for the purpose of higher data rates, low delay and the like, Long Term Evolution (LTE) has been specified (Non-Patent Document 1). For the purpose of wider bands and a higher speed than LTE, LTE Advanced has been specified, and a successor system of LTE that is called, for example, FRA (Future Radio Access) has been studied. A system band according to LTE Rel.10/11 includes at least one component carrier (CC) whose one unit is a system band of an LTE system. Aggregating a plurality of component carriers and widening a band in this way are referred to as carrier aggregation (CA). According to LTE Rel.12 that is another successor system of LTE, various scenarios for using a plurality of cells in different frequency bands (carriers) have been studied. When radio base stations that form a plurality of cells are substantially identical, the above-described carrier aggregation is applicable. When radio base stations that form a plurality of cells are completely different, it is considered to apply dual connectivity (DC). Citation List Non-Patent Literature [Non-Patent Literature 1] 3GPP TS 36.300 "Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2" US 2013/0279480 A1 discloses a method for configuring and transmitting an HARQ ACK/NACK signal by bundling said signal about a component carrier wave of a downlink subframe linked with an uplink subframe transmitting an HARQ ACK/NACK signal on PUCCH format 3. More particularly, the method comprises the steps of: determining a mode for bundling an HARQ ACK/NACK signal; and configuring the bundled HARQ ACK/NACK signal according to the determined bundling mode, wherein in the step of determining the bundling mode, all the component carriers of the downlink subframe transmitting the HARQ ACK/NACK signal to an uplink subframe are bundled when the downlink channel is in a worse state than the predetermined reference state, and some of the component carriers of the downlink subframe transmitting the HARQ ACK/NACK signal to an uplink subframe are bundled when the downlink channel is not in a worse state. US 2014/0056187 Al discloses methods and an apparatus for a User Equipment (UE) configured with multiple cells in a DownLink (DL) of a Time Division Duplex (TDD) communication system to determine the coding method for acknowledgement information bits as a function of their number, to apply bundling to the acknowledgement information bits when their number exceeds a first predetermined value, and to partition the acknowledgement information bits, possibly together with other control information bits, into two separate codewords when their total number exceeds a second predetermined value. Summary of Invention Technical Problem According to carrier aggregation according to LTE Rel.10/11/12, the number of component carriers that can be configured per user terminal is limited to five at maximum. According to LTE Rel.13 and subsequent versions, the number of component carriers that can be configured per user terminal is six or more to realize more flexible and higher speed radio communication, and enhanced carrier aggregation for bundling these component carriers has been studied. According to LTE Rel.10/11/12, PUCCH (Physical Uplink Control Channel) format 1b with channel selection that is applicable to two component carriers at maximum and PUCCH format 3 that is applicable to five component carriers at maximum have been introduced as a HARQ-ACK (Hybrid Automatic Repeat Request Acknowledgement) transmitting method using a PUCCH. However, according to the enhanced carrier aggregation where the number of component carriers that can be configured per user terminal is six or more, how to transmit HARQ-ACK has not yet been defined. The present invention has been made in view of such a respect, and it is an object of the invention to provide a user terminal, a radio communication system and a radio communication method for appropriately transmitting HARQ-ACK during enhanced carrier aggregation. Accordingly, the present invention provides a user terminal according to claim 1. The present invention also provides a radio communication method of a user terminal, in accordance with claim 5. The present invention also provides a base station, in accordance with claim 6. The present invention also provides a system comprising a user terminal and a base station, in accordance with claim 7. The invention is defined by the appended claims. According to the present invention, it is possible tc appropriately transmit HARQ-ACK during enhanced carrier aggregation. Brief Description of Drawings FIGs. 1 contain diagrams for explaining a PUCCH format 3 in a cas