TECHNICAL FIELD

The present invention relates to a radio terminal, a transmission power control method, and a radio base station.

BACKGROUND ART

Long Term Evolution (LTE) has been specified for achieving a higher data rate, lower latency, and the like in a Universal Mobile Telecommunications System (UMTS) network (see Non-Patent Literature (hereinafter referred to as “NPL”) 1). Successor systems of LTE have been also studied for achieving a broader bandwidth and a higher speed based on LTE. Examples of successor systems of LTE include the systems called LTE-A (LTE-Advanced), FRA (Future Radio Access), 5G (5th generation mobile communication system), 5G+ (5G plus), and New-RAT (Radio Access Technology)).

Use of Massive Multiple Input Multiple Output (MIMO) using a large number of antenna elements (at least 100 elements, for example) in a high-frequency band (at least 4 GHz, for example) has been studied for the future radio communication system (for example, 5G) for a further increase in speed of signal transmission and reduction in interference. Further, a radio communication system based on an ultrahigh-density distributed antenna system including a signal processing unit and transmission points each including at least one antenna element has been studied (NPL 1, for example).

CITATION LIST

Non-Patent Literature

NPL 1T. Okuyama et. al.: “Antenna Deployment for 5G Ultra High-Density Distributed Antenna System at Low SHF Bands” Standards for Communications and Networking (CSCN), 2016, pp. 1-6, November 2016, Berlin, Germany

SUMMARY OF INVENTION

Technical Problem

However, at present, no proposal has been made for improvement in communication quality by performing transmission power control on a radio terminal that performs radio communication with a transmission point.

In view of the circumstances described above, an object of the present invention is to provide a technology for improving communication quality by performing transmission power control on a radio terminal that performs radio communication with a transmission point.

Solution to Problem

A radio terminal according to the present invention is a radio terminal that performs radio communication with a radio base station including: a plurality of transmission points each including at least one antenna element; and a signal processing unit connected to the plurality of transmission points, the radio terminal including: a plurality of antenna elements; an estimating section that estimates path-loss between each of the plurality of antenna elements and the plurality of transmission points; and a calculating section that calculates a power control weight for controlling transmission power of each of the plurality of antenna elements based on the path-loss for the antenna element that has been estimated by the estimating section.

Advantageous Effects of Invention

The present invention allows improvement in communication quality by performing transmission power control on a radio terminal that performs radio communication with a transmission point.

