# US 5,347,535 A · CDMA communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,347,535 A - Document ID: US5347535A - Status: Granted - Kind: A - Application number: 08/025,659 - Filed: 1993-03-03 - Granted: 1994-09-13 - Earliest claimed: 1992-03-18 - Assignees: Kokusai Denshin Denwa Kabushiki Kaisha - Inventors: Yoshio Karasawa; Hisato Iwai - Web page: https://patentgrep.com/patent/US5347535A ## CPC - H04B 7/0894: {using different delays between antennas} - H04B: TRANSMISSION ## Abstract A CDMA communication system using a spreading code has a plurality of mobile stations and at least one base station. The mobile stations and the base station are provided with respective receiving sections, each of which has a path diversity function for reducing multipath fading. The base station includes an array antenna having a plurality of integrated antenna elements spaced by a distance substantially equal to one to several wavelengths from each other so as to produce a space diversity effect. A plurality of delay devices are coupled with the respective antenna elements, for applying time delays to signals which pass through the respective antenna elements. The time delay are different from each other by a one symbol period of the spreading code or more. ## Claims ### Claim 1 A CDMA communication system using spreading codes, said system having a plurality of mobile stations and at least one base station, said mobile stations and said base station provided with respective receiving sections each of which has a path diversity function for reducing multipath fading, said base station comprising: an array antenna having a plurality of integrated antenna elements spaced by a distance substantially equal to one to several wavelengths from each other so as to produce a space diversity effect; and a plurality of delay means coupled with said respective antenna elements, for applying time delays to signals which pass through said respective antenna elements, said time delay being different from each other by a one symbol period of the spreading codes or more. ### Claim 2 (depends on 1) A system as claimed in claim 1, wherein said delay means are formed by optical fiber cables coupled with said respective antenna elements, each length of the optical fiber cables being adjusted so that the difference of the delay between the cables corresponds to a one symbol period of the spreading code or more. ### Claim 3 (depends on 1) A system as claimed in claim 1, wherein said receiving section includes a correlator for calculating a correlation between signals received at said receiving section and a spreading code assigned to a particular mobile station, and a tapped delay line connected to said correlator, for realizing the path diversity function. ### Claim 4 (depends on 2) A system as claimed in claim 2, wherein said array antenna is a receiver antenna for receiving signals from said mobile stations, wherein said base station includes electro-optical converters inserted between said respective antenna elements and one ends of said respective optical fiber cables, an optical combining means coupled with the other ends of said optical fiber cables, and an opto-electrical converter coupled with said optical combining means. ### Claim 5 (depends on 4) A system as claimed in claim 4, wherein said base station further includes a correlator for calculating a correlation between signals fed from said opto-electrical converter and a spreading code used for modulating signals to be transmitted at a particular mobile station, and a tapped delay line connected to said correlator, for realizing the path diversity function. ### Claim 6 (depends on 2) A system as claimed in claim 2, wherein said array antenna is a transmitter antenna for transmitting signals to said mobile stations, wherein said base station includes opto-electrical converters inserted between said respective antenna elements and one ends of said respective optical fiber cables, an optical distributing means coupled with the other ends of said optical fiber cables, and a electro-optical converter coupled with said optical distributing means. ### Claim 7 (depends on 2) A system as claimed in claim 2, wherein said array antenna is an antenna for receiving and transmitting signals from and to said mobile stations, wherein said base station includes first electro-optical converters inserted between said respective antenna elements and one ends of respective first set of said optical fiber cables, an optical combining means coupled with the other ends of said first set of said optical fiber cables, a first opto-electrical converter coupled with said optical combining means, second opto-electrical converters inserted between said respective antenna elements and one ends of respective second set of said optical fiber cables, an optical distributing means coupled with the other ends of said second set of said optical fiber cables, and a second electro-optical converter coupled with said optical distributing means. ### Claim 8 (depends on 7) A system as claimed in claim 7, wherein said base station further includes a correlator for calculating a correlation between signals fed from said first opto-electrical converter and a spreading code used for modulating signals to be transmitted at a particular mobile station, and a tapped delay line connected to said correlator, for realizing the path diversity function. ### Claim 9 A base station for a CDMA communication system using spreading codes, said system having a plurality of mobile stations, said base station provided with a receiving section which has a path diversity function for reducing multipath fading, comprising: an array antenna having a plurality of integrated antenna elements spaced by a distance substantially equal to one to several wavelengths from each other so as to produce a space diversity effect; and a plurality of delay means coupled with said respective antenna elements, for applying time delays to signals which pass through said respective antenna elements, said time delay being different from each other by a one symbol period of the spreading codes or more. ### Claim 10 (depends on 9) A base station as claimed in claim 9, wherein said delay means are formed by optical fiber cables coupled with said respective antenna elements, each length of the optical fiber cables being adjusted so that the difference of the delay between the cables corresponds to a one symbol period of the spreading code or more. ### Claim 11 (depends on 9) A base station as claimed in claim 9, wherein said receiving section includes a correlator for calculating a correlation between signals received at said receiving section and a spreading code assigned to a particular mobile station, and a tapped delay line connected to said correlator, for realizing the path diversity function. ### Claim 12 (depends on 10) A base station as claimed in claim 10, wherein said array antenna is a receiver antenna for receiving signals from said mobile stations, wherein said base station includes electro-optical converters inserted between said respective antenna elements and one ends of said respective optical fiber cables, an optical combining means coupled with the other ends of said optical fiber cables, and an opto-electrical converter coupled with said optical combining means. ### Claim 13 (depends on 12) A base station as claimed in claim 12, wherein said base station further includes a correlator for calculating a correlation between signals fed from said opto-electrical converter and a spreading code used for modulating signals to be transmitted at a particular mobile station, and a tapped delay line connected to said correlator, for realizing the path diversity function. ### Claim 14 (depends on 10) A base station as claimed in claim 10, wherein said array antenna is a transmitter antenna for transmitting signals to said mobile stations, wherein said base station includes opto-electrical converters inserted between said respective antenna elements and one ends of said respective optical fiber cables, an optical distributing means coupled with the other ends of said optical fiber cables, and a electro-optical converter coupled with said optical distributing means. ### Claim 15 (depends on 10) A base station as claimed in claim 10, wherein said array antenna is an antenna for receiving and transmitting signals from and to said mobile stations, wherein said base station includes first electro-optical converters inserted between said respective antenna elements and one ends of respective first set of said optical fiber cables, an optical combining means coupled with the other ends of said first set of said optical fiber cables, a first opto-electrical converter coupled with said optical combining means, second opto-electrical converters inserted between said respective antenna elements and one ends of respective second set of said optical fiber cables, an optical distributing means coupled with the other ends of said second set of said optical fiber cables, and a second electro-optical converter coupled with said optical distributing means. ### Claim 16 (depends on 15) A base station as claimed in claim 15, wherein said base station further includes a correlator for calculating a correlation between signals fed from said first opto-electrical converter and a spreading code used for modulating signals to be transmitted at a particular mobile station, and a tapped delay line connected to said correlator, for realizing the path diversity function. ### Claim 17 An antenna section in a base station of a CDMA communication system using spreading codes, said system having a plurality of mobile stations, said mobile stations and said base station provided with respective receiving sections each of which has a path diversity function for reducing multipath fading, comprising: an array antenna having a plurality of integrated antenna elements spaced by a distance substantially equal to one to several wavelengths from each other so as to produce a space diversity effect; and a plurality of delay means coupled with said respective antenna elements, for applying time delays to signals which pass through said respective antenna elements, said time delay being different from each other by a one symbol period of the spreading codes or more. ### Claim 18 (depends on 17) An antenna section as claimed in claim 17, wherein said delay means are formed by optical fiber cables coupled with said respective antenna elements, each length of the optical fiber cables being adjusted so that the difference of the delay between the cables corresponds to a one symbol period of the spreading code or more.