# US 9,521,604 B2 · User terminal, radio base station and radio communication method

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- Number: US 9,521,604 B2
- Document ID: US9521604B2
- Status: Granted
- Kind: B2
- Application number: 13/883,426
- Filed: 2011-11-08
- Published: 2013-11-21
- Granted: 2016-12-13
- Earliest claimed: 2010-11-09
- Assignees: Ntt Docomo, Inc.
- Applicants: Tetsushi Abe; Satoshi Nagata; Nobuhiko Miki; Naoto Ookubo
- Inventors: Tetsushi Abe; Satoshi Nagata; Nobuhiko Miki; Naoto Ookubo
- Web page: https://patentgrep.com/patent/US9521604B2

## CPC

- H04W 68/005: {Transmission of information for alerting of incoming communication}
- H04L 5/0096: {Indication of changes in allocation}
- H04W 68/02: Arrangements for increasing efficiency of notification or paging channel
- H04B 17/382: for resource allocation, admission control or handover
- H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT}
- H04L 5/005: {of common pilots, i.e. pilots destined for multiple users or terminals}
- H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals}
- H04L 5/0073: {Allocation arrangements that take into account other cell interferences}
- H04W 36/04: Reselecting a cell layer in multi-layered cells
- H04W 52/40: during macro-diversity or soft handoff
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04B: TRANSMISSION

## Abstract

In order to transmit a paging to a user terminal with high quality, transmit a CSI-RS effectively and perform UL HARQ efficiently in HetNet, the present invention provides a radio communication method having the steps of: a micro base station which is arranged in a macro cell and forms a smaller micro cell than the macro cell, transmitting, to a user terminal, a signal having a CSI-RS subframe including a CSI-RS and a paging subframe including modification notification information indicating modification in system information and a control signal indicating not to measure a CSI-RS when the CSI-RS subframe and the paging subframe collide with each other; and the user terminal determining a CSI-RS subframe to measure the CSI-RS based on the control signal when the CSI-RS subframe and the paging subframe collide with each other.

## Claims

### Claim 1

A user terminal for receiving a CSI-RS (Channel State Information-Reference Signal) periodically transmitted in a CSI-RS subframe and a paging transmitted in at least one of paging subframes, the user terminal comprising:
a receiving section configured to receive system information indicating which subframe of the paging subframes to transmit the paging;
a subframe determining section configured to determine a CSI-RS subframe to measure a CSI-RS based on the system information, when the CSI-RS subframe and the paging subframes collide with each other; and
a measuring section that measures the CSI-RS determined by the subframe determining section,
wherein the paging includes modification notification information indicating modification in the system information.

### Claim 2 (depends on 1)

The user terminal of claim 1, wherein the subframe determining section is configured to determine a subframe in which the paging is not transmitted out of the paging subframes to be the CSI-RS subframe to measure the CSI-RS.

### Claim 3 (depends on 1)

The user terminal of claim 1, wherein the subframe determining section is configured to determine a subframe in which the paging is transmitted out of the paging subframes not to be the CSI-RS subframe to measure the CSI-RS.

### Claim 4

A radio communication method in a user terminal receiving a CSI-RS (Channel State Information-Reference Signal) periodically transmitted in a CSI-RS subframe and a paging transmitted in at least one of paging subframes, the radio communication method comprising the steps of:
receiving system information indicating which subframe of the paging subframes to transmit the paging; and
determining a CSI-RS subframe to measure a CSI-RS based on the system information, when the CSI-RS subframe and the paging subframes collide with each other; and
measuring the determined CSI-RS subframe,
wherein the paging includes modification notification information indicating modification in the system information.

### Claim 5 (depends on 4)

The radio communication method of claim 4, wherein in the step of determining the CSI-RS subframe, a subframe in which the paging is not transmitted out of the paging subframes is determined to be the CSI-RS subframe to measure the CSI-RS.

### Claim 6 (depends on 4)

The radio communication method of claim 4, wherein in the step of determining the CSI-RS subframe, a subframe in which the paging is transmitted out of the paging subframes is determined not to be the CSI-RS subframe to measure the CSI-RS.

### Claim 7

A radio communication system having a user terminal that receives a CSI-RS (Channel State Information-Reference Signal) periodically transmitted in a CSI-RS subframe and a paging transmitted in at least one of paging subframes, comprising:
a receiving section configured to receive system information indicating which subframe of the paging subframes to transmit the paging;
a subframe determining section configured to determine a CSI-RS subframe to measure a CSI-RS based on the system information, when the CSI-RS subframe and the paging subframes collide with each other; and
a measuring section that measures the CSI-RS determined by the subframe determining section,
wherein the paging includes modification notification information indicating modification in the system information.