# US 2018/0027501 A1 · Radio communication method, local area base station apparatus, mobile terminal apparatus and radio communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0027501 A1 - Document ID: US20180027501A1 - Status: Published application - Kind: A1 - Application number: 15/719,894 - Filed: 2017-09-29 - Published: 2018-01-25 - Earliest claimed: 2012-04-06 - Assignees: Ntt Docomo, Inc. - Applicants: Ntt Docomo, Inc. - Inventors: Yoshihisa Kishiyama; Anass Benjebbour; Kazuaki Takeda - Web page: https://patentgrep.com/patent/US20180027501A1 ## CPC - H04W 52/242: {taking into account path loss} - H04B 17/318: Received signal strength - H04W 16/18: Network planning tools - H04W 24/02: Arrangements for optimising operational condition - H04W 52/241: {taking into account channel quality metrics, e.g. SIR, SNR, CIR or Eb/lo} - H04L 1/0026: {Transmission of channel quality indication} - H04L 5/0057: {Physical resource allocation for CQI} - H04W 16/32: Hierarchical cell structures - H04W 48/10: using broadcasted information - H04W 52/143: {Downlink power control} - H04W 52/146: {Uplink power control} - H04W 52/247: {where the output power of a terminal is based on a path parameter sent by another terminal} - H04W 52/325: {Power control of control or pilot channels} - H04W 52/50: at the moment of starting communication in a multiple access environment - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A radio communication method is provided in which a local area base station apparatus, arranged in a wide area where a first carrier frequency is used and forming a local area that is narrower than the wide area, transmits a downlink signal, using a second carrier frequency, which belongs to a different frequency band from the first carrier frequency and which has a wider bandwidth than the first carrier frequency, the local area base station apparatus transmits a detection signal that is used to detect the local area base station apparatus in the mobile terminal apparatus, and the local area base station apparatus transmits the downlink signal for the mobile terminal apparatus with transmission power that is determined based on the path loss of the detection signal received in the mobile terminal apparatus. ## Claims ### Claim 1 A mobile terminal apparatus that communicates with a first radio base station forming a first cell and a second radio base station forming a second cell, the mobile terminal apparatus comprising: a receiving section that receives, from the first radio base station, information about transmission power of a downlink signal and transmission power of a CSI-RS (Channel State Information Reference Signal) in the second cell; a generating section that uses the information as a basis to generate a CQI (Channel Quality Indicator) used for transmission of the downlink signal in the second cell; and a transmission section that transmits the CQI by using a PUCCH (Physical Uplink Control Channel) in the second cell. ### Claim 2 (depends on 1) The mobile terminal apparatus according to claim 1, wherein the receiving section receives the information from the first radio base station by higher layer signaling or broadcast information. ### Claim 3 (depends on 1) The mobile terminal apparatus according to claim 1, wherein the transmission power of the downlink signal is controlled based on the CQI. ### Claim 4 (depends on 1) The mobile terminal apparatus according to claim 1, wherein the first radio base station is unable to turn downlink transmission on and off, and the second radio base station is able to turn downlink transmission on and off. ### Claim 5 A second radio base station forming a second cell, the second radio base station comprising: a receiving section that receives CQI (Channel Quality Indicator) that is generated based on a CSI-RS (Channel State Information Reference Signal) in the second cell; and a transmission section that transmits a downlink signal in the second cell based on the CQI, wherein the CQI is generated based on information about transmission power of the downlink signal and transmission power of the CSI-RS and the information is transmitted from a first radio base station forming a first cell. ### Claim 6 (depends on 5) The second radio base station according to claim 5, wherein the information is transmitted from the first radio base station by higher layer signaling or broadcast information. ### Claim 7 (depends on 5) The second radio base station according to claim 5, further comprising a control section that controls the transmission power of the downlink signal based on the CQI. ### Claim 8 (depends on 5) The second radio base station according to claim 5, wherein the first radio base station is unable to turn downlink transmission on and off, and the second radio base station is able to turn downlink transmission on and off. ### Claim 9 A radio communication method for a mobile terminal apparatus that communicates with a first radio base station forming a first cell and a second radio base station forming a second cell, the radio communication method comprising: receiving, from the first radio base station, information about transmission power of a downlink signal and transmission power of a CSI-RS (Channel State Information Reference Signal) in the second cell; using the information as a basis to generate a CQI (Channel Quality Indicator) used for transmission of the downlink signal in the second cell; and transmitting the CQI in the second cell. ### Claim 10 (depends on 2) The mobile terminal apparatus according to claim 2, wherein the transmission power of the downlink signal is controlled based on the CQI. ### Claim 11 (depends on 2) The mobile terminal apparatus according to claim 2, wherein the first radio base station is unable to turn downlink transmission on and off, and the second radio base station is able to turn downlink transmission on and off. ### Claim 12 (depends on 3) The mobile terminal apparatus according to claim 3, wherein the first radio base station is unable to turn downlink transmission on and off, and the second radio base station is able to turn downlink transmission on and off. ### Claim 13 (depends on 6) The second radio base station according to claim 6, further comprising a control section that controls the transmission power of the downlink signal based on the CQI. ### Claim 14 (depends on 6) The second radio base station according to claim 6, wherein the first radio base station is unable to turn downlink transmission on and off, and the second radio base station is able to turn downlink transmission on and off. ### Claim 15 (depends on 7) The second radio base station according to claim 7, wherein the first radio base station is unable to turn downlink transmission on and off, and the second radio base station is able to turn downlink transmission on and off.