TECHNICAL FIELD

The present invention relates to a base station apparatus, a terminal apparatus, a communication method, and an integrated circuit.

This application claims priority based on JP 2017-017375 filed on Feb. 2, 2017, the contents of which are incorporated herein by reference.

BACKGROUND ART

Currently, the Third Generation Partnership Project (3GPP) is conducting a technical study and standardization of Long Term Evolution (LTE)-Advanced Pro and New Radio technology (NR) as a radio access method and a radio network technology for the 5th generation cellular system (NPL 1).

In the 5th generation cellular system, three technologies are required for the expected service scenario, that is, enhanced Mobile BroadBand (eMBB) to realize a high-speed and high-capacity transmission, Ultra-Reliable and Low Latency Communication (URLLC) to realize a low delay and highly reliable communication, and massive Machine Type Communication (mMTC), such as Internet of Things (IoT), that allows a large number of machine type devices to be connected.

In NR, reference signals for tracking phase noise generated by an oscillator have been studied for communication at high frequencies. (NPL 2).

CITATION LIST

Non Patent Literature

NPL 1: RP-161214, NTT DOCOMO, “Revision of SI: Study on New Radio Access Technology”, June 2016

NPL 2: R1-1701435, Mitsubishi Electric, CATT, InterDigital, Intel, Qualcomm, “WF on PT-RS for DFTs OFDM”, January 2017

SUMMARY OF INVENTION

Technical Problem

An object of the present invention is to provide a terminal apparatus, a base station apparatus, a communication method, and an integrated circuit for efficiently communicating in the above-mentioned radio communication systems.

Solution to Problem

(1) To accomplish the object described above, aspects of the present invention are contrived to provide the following measures. A terminal apparatus according to one aspect of the present invention is a terminal apparatus for communicating with a base station apparatus, the terminal apparatus including: a transmission unit configured to transmit Phase-tracking reference signals (PTRS), and an higher layer processing unit configured to configure information for indicating a time density and/or a frequency density of the PTRS. A PTRS pattern is configured such that the time density of the PTRS is higher for a larger Modulation and Coding Scheme (MCS) scheduled for the terminal apparatus, and the frequency density of the PTRS is based on the number of resource blocks scheduled for the terminal apparatus.

(2) In the terminal apparatus according to one aspect of the present invention, the PTRS are not generated in accordance with a rule based on the MCS and/or the number of resource blocks scheduled for the terminal apparatus.

(3) In the terminal apparatus according to one aspect of the present invention, the PTRS are selected from a plurality of the PTRS patterns defined in advance.

(4) In the terminal apparatus according to one aspect of the present invention, information for indicating the time density and/or the frequency density of the PTRS includes information for indicating the PTRS pattern.

(5) In the terminal apparatus according to one aspect of the present invention, the transmission unit transmits capability information for indicating whether a capability of transmitting PTRS signals is supported.

(6) A base station apparatus according to one aspect of the present invention is a base station apparatus for communicating with a terminal apparatus, the base station apparatus including: a reception unit configured to receive Phase-tracking reference signals (PTRS); and a higher layer processing unit configured to configure information for indicating a time density and a frequency density of the PTRS, in the terminal apparatus. The terminal apparatus uses the time density of the PTRS which is higher for a larger Modulation and Coding Scheme (MCS) scheduled for the terminal apparatus is higher, and the frequency density of the PTRS is based on the number of scheduled resource blocks for the terminal apparatus.

Advantageous Effects of Invention

According to one aspect of the present invention, a base station apparatus and a terminal apparatus efficiently communicate with each other.

