# US 2018/0026690 A1 · Transmission control device, radio communication system, and calibration method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0026690 A1 - Document ID: US20180026690A1 - Status: Published application - Kind: A1 - Application number: 15/636,883 - Filed: 2017-06-29 - Published: 2018-01-25 - Earliest claimed: 2016-07-20 - Assignees: Fujitsu Limited - Applicants: Fujitsu Limited - Inventors: Daisuke JITSUKAWA; TAKASHI DATEKI - Web page: https://patentgrep.com/patent/US20180026690A1 ## CPC - H04B 7/0613: {using simultaneous transmission (H04B7/0686 takes precedence)} - H01Q 3/267: {Phased-array testing or checking devices} - H04B 1/405: with multiple discrete channels - H04B 7/005: Control of transmission; Equalising - H04B 7/12: Frequency diversity - H04B 7/208: Frequency-division multiple access {[FDMA]} - H04B 7/2126: {using a reference station} - H04B 17/11: for calibration - H04B 17/21: for calibration; for correcting measurements - H04B 17/309: Measuring or estimating channel quality parameters - H04B: TRANSMISSION - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) ## Abstract A transmission control device includes a memory and a processor connected to the memory. The processor executes a process including: selecting a reference transmission point as a starting point of generating a link from among a plurality of transmission points of which each wirelessly transmits a signal; sequentially selecting the transmission points one by one for each hierarchy corresponding to a number of hops from the selected reference transmission point and retrieving ones of the transmission points for which radio quality between the ones and the selected transmission point satisfies a predetermined criterion; and generating a link between the selected transmission point and a transmission point, among the transmission points obtained as a result at the retrieving, not connected to others of the transmission points to connect the two transmission points. ## Claims ### Claim 1 A transmission control device comprising: a memory; and a processor connected to the memory, wherein the processor executes a process comprising: selecting a reference transmission point as a starting point of generating a link from among a plurality of transmission points of which each wirelessly transmits a signal; sequentially selecting the transmission points one by one for each hierarchy corresponding to a number of hops from the selected reference transmission point and retrieving ones of the transmission points for which radio quality between the ones and the selected transmission point satisfies a predetermined criterion; and generating a link between the selected transmission point and a transmission point, among the transmission points obtained as a result at the retrieving, not connected to others of the transmission points to connect the two transmission points. ### Claim 2 (depends on 1) The transmission control device according to claim 1, wherein the process further comprises: causing the plurality of transmission points to transmit and receive a calibration signal via the link generated between the plurality of transmission points; and computing, based on a channel estimation result that uses the calibration signal, a calibration coefficient calibrating a difference between transmission characteristics of a transmitter circuit and a receiver circuit included in the plurality of transmission points. ### Claim 3 (depends on 2) The transmission control device according to claim 2, wherein the causing includes: causing a plurality of transmission points belonging to one of an even hierarchy and an odd hierarchy to simultaneously transmit the calibration signal; and causing a transmission point belonging to another of the even hierarchy and the odd hierarchy to receive the transmitted calibration signal. ### Claim 4 (depends on 1) The transmission control device according to claim 1, wherein the memory stores an error table that stores a calibration error to be expected every radio quality in association with each other, and the process further comprises: computing, with reference to the error table, an accumulated error obtained by accumulating calibration errors corresponding to radio quality of links between the reference transmission point and the other transmission points; and modifying the links generated between the reference transmission point and the other transmission points when the computed accumulated error is not less than a predetermined threshold. ### Claim 5 A radio communication system that includes a transmission control device and a plurality of transmission points connected to the transmission control device, the transmission control device comprising: a memory; and a processor connected to the memory, wherein the processor executes a process comprising: selecting a reference transmission point as a starting point of generating a link from among the plurality of transmission points of which each wirelessly transmits a signal; sequentially selecting the transmission points one by one for each hierarchy corresponding to a number of hops from the selected reference transmission point and retrieving ones of the transmission points for which radio quality between the ones and the selected transmission point satisfies a predetermined criterion; and generating a link between the selected transmission point and a transmission point, among the transmission points obtained as a result at the retrieving, not connected to others of the transmission points to connect the two transmission points, and each of the transmission points comprising: a transmitter circuit that performs a radio transmission process on a calibration signal and transmits the calibration signal after the radio transmission process via the generated link; and a receiver circuit that receives a calibration signal via the generated link and performs a radio reception process on the received calibration signal. ### Claim 6 A calibration method comprising: selecting, using a processor, a reference transmission point as a starting point of generating a link from among a plurality of transmission points of which each wirelessly transmits a signal; sequentially selecting, using the processor, the transmission points one by one for each hierarchy corresponding to a number of hops from the selected reference transmission point and retrieving, using the processor, ones of the transmission points for which radio quality between the ones and the selected transmission point satisfies a predetermined criterion; and generating, using the processor, a link between the selected transmission point and a transmission point, among the transmission points obtained as a result at the retrieving, not connected to others of the transmission points to connect the two transmission points; transmitting and receiving a calibration signal via the link generated between the plurality of transmission points; and computing, using the processor, based on a channel estimation result that uses the calibration signal, a calibration coefficient calibrating a difference between transmission characteristics of a transmitter circuit and a receiver circuit included in the plurality of transmission points.