Information communication system using multi-code CDMA mode
AssigneeKabushiki Kaisha Toshiba
InventorsHirokazu Tanaka, Tatsunori Saito
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Abstract
A system adaptively determines the number of spread codes to use and a type of multi-valued modulation system based on the station of the system. Transmission information is divided into a number of sequences equal to the number of used spread codes. These sequences are error correction encoded, primarily modulated according to a selected one of a plurality of types of multi-valued modulation schemes, secondarily modulated by the selected spread codes, and transmitted.
Claims19
An information communication system wherein a first information communication apparatus and a second information communication apparatus perform information communication by a spread spectrum system within a frequency band predetermined for MC-CDMA communication by selecting usable spread codes from a plurality of spread codes provided by the system, the information communication system comprising:
- communication mode determining means for adaptively determining a combination between a type of multi-level modulation scheme and the number of spread codes assigned to communication between the first and second information communication apparatuses, the combination being determined based on a traffic amount of the information communication system such that the combination enables an optimal transmission efficiency within the frequency band;
- dividing means for dividing transmission information into information sequences corresponding in number to the spread codes which are assigned to the communication as determined by the communication mode determining means;
- encoding means for performing error correction encoding with respect to the information sequences output from the dividing means;
- primarily modulating means for primarily modulating the information sequences subjected to the error correction encoding by the encoding means on the basis of the multi-level modulation scheme determined by the communication determining means;
- and
- secondarily modulating means for selecting at least one spread code, which corresponds in number to the spread codes assigned to the communication as determined by the communication mode determining means, from the plurality of spread codes provided by the information communication system, and for secondarily modulating to transmit the selected spread code for the modulation signal sequence output from the primarily modulating means.
An information communication system wherein a first information communication apparatus and a second information communication apparatus perform information communication by a spread spectrum system within a frequency band predetermined for MC-CDMA communication by selecting usable first spread codes from a plurality of first spread codes provided by the system and usable second spread codes from a plurality of second spread codes provided by the system, the information communication system comprising:
- communication mode determining means for adaptively determining a combination among a type of multi-level modulation scheme, the number of first spread codes assigned to communication between the first and second information communication apparatuses and the number of second spread codes assigned to the communication, the combination being determined based on a traffic amount of the information communication system such that the combination enables an optimal transmission efficiency within the frequency band;
- dividing means for dividing transmission information into information sequences corresponding in number to the first spread codes which are assigned to the communication as determined by the communication mode determining means;
- encoding means for performing error correction encoding with respect to the information sequences output from the dividing means;
- primarily modulating means for primarily modulating the information sequences subjected to the error correction encoding by the encoding means on the basis of the multi-level modulation scheme determined by the communication determining means;
- and
- secondarily spread modulating means for selecting at least one second spread code, which corresponds in number to the spread codes assigned to the communication as determined by the communication mode determining means, from the plurality of second spread codes provided by the information communication system, and for secondarily modulating to transmit the selected second spread code for the modulation signal sequence output from the primarily modulating means.
An information communication apparatus for a mobile information communication system that provides a plurality of spread codes and selectively uses the plurality of spread codes for communication between a mobile station and a base station to transmit information, the information communication apparatus comprising:
- communication mode determining means for adaptively determining a combination between a type of multi-level modulation scheme and the number of spread codes assigned to the communication between the mobile station and the base station, the combination being determined based on a traffic amount of the information communication system such that the combination enables an optimal transmission efficiency within the frequency band;
- and
- communication mode informing means for informing the mobile station of the determined combination between a type of multi-level modulation scheme and the number of spread codes assigned to the communication.
An information communication apparatus to be used as a mobile station for a mobile information communication system that provides a plurality of spread codes and selectively uses the plurality of spread codes between the mobile station and a base station to transmit information by a spread spectrum system, the information communication apparatus comprising:
- communication mode determining means for adaptively determining a combination between a type of multi-level modulation scheme and the number of spread codes assigned to communication between the mobile station and the base station, the combination being determined based on a traffic amount of the information communication system such that the combination enables an optimal transmission efficiency within the frequency band;
- dividing means for dividing transmission information into information sequences corresponding in number to the spread codes which are assigned to the communication as determined by the communication mode determining means;
- encoding means for performing error correction encoding with respect to the information sequences output from the dividing means;
- modulating means for selecting the multi-level modulation scheme determined by the communication mode determining means from a plurality of types of multi-level modulations for error correction encoding, and for modulating the information sequences subjected to error correction encoding by the encoding means according to the selected multi-level modulation system;
- and
- spread modulating means for selecting at least one spread code, which corresponds in number to the spread codes assigned to the communication as determined by the communication mode determining means, from the plurality of spread codes provided by the information communication system, and for spread modulating the modulation signal sequence output from the modulation means by the selected spread code to transmit the signal sequence.
Dependencies are inferred from the claim text.