摘要:
A contactless IC card having an antenna, a transmit/receive circuit for recovering data (clock) and electric power from a carrier signal received by the antenna, a logic circuit operated with the electric power supplied thereto from the transmit/receive circuit, and a memory. The transmit/receive circuit has a rectifier circuit for outputting data (clock) and rectifier circuits for electric power in such a manner that the carrier signal is inputted to each of the rectifier circuit for outputting data (clock) and the rectifier circuit for electric power. With this configuration, high frequency matching can be optimized separately for the rectifier circuit for outputting data (clock) and the rectifier circuit for electric power. It is also possible to separately optimize adjustments to a voltage of recovered data (clock) and a recovered supply voltage.
摘要:
In a conventional method which defines an authentication key for each record, as the number of the records is increased in an access right management for records in a memory of an IC card, the number of the types of authentication keys is also increased to require a larger memory area for storing the authentication keys, thus causing lower memory efficiency. In order to solve such a problem, terminal types (ex. “0H”-“7H”) are defined for interrogators, so that only the number of authentication keys equal to the number of the terminal types are stored. Each record has the number of access permission bits equal to the number of the terminal types, and specifies terminal types, to which an access is permitted, by setting the bits ON or OFF.
摘要:
In a wireless communication system for communicating with a plurality of stations at the same point of time with the same frequency using a Space Division Multiple Access (SDMA), wireless resources are allocated by a first decision unit which evaluates performance of each station obtained when the SDMA is used and which determines periods of time to be allocated to groups of stations formed according to the SDMA technique. Using a first evaluation unit and a second evaluation unit to evaluate performance required by each station and each application, the first decision unit allocates the wireless resources to the stations. It is therefore possible that the wireless resources are efficiently allocated to the stations while preventing an event in which the wireless resources are excessive or insufficient for required quality of service.
摘要:
Disclosed is a wireless communication system capable of performing demodulation at the receiving side without substantially deteriorating BER characteristics, regardless of carrier frequency error existing among plural wireless communication systems in SDMA of uplink. The wireless communication system includes plural antennas; a MIMO processor that decomposes a reception signal the plural antennas received from plural transmitters into transmission signals transmitted from the respective transmitters; a FFT processor that carries out OFDM demodulation; and a demapping unit that obtains data from signals which were previously converted into sub-carrier signals by the FFT processor, in which the MIMO processor is installed ahead of the FFT processor for sake of the processing sequence of a receive signal, and even though a carrier frequency offset exists in the reception signal MIMO processing is performed prior to OFDM demodulation to split the reception signal from plural transmitters.
摘要:
A charging system for use in a network composed of wireless terminals with a repeater function. As each terminal with a repeater function receives a communication session start request from a user terminal, it searches for a destination user terminal; when it finds the destination user terminal, it transfers the signal sent from the requesting user terminal to the destination user terminal without the mediation of base stations. The information about the amount of data thus transferred or communication time for transferring data is sent to the charging system which is under the control of the communications service provider concerned.
摘要:
In a conventional method which defines an authentication key for each record, as the number of the records is increased in an access right management for records in a memory of an IC card, the number of the types of authentication keys is also increased to require a larger memory area for storing the authentication keys, thus causing lower memory efficiency. In order to solve such a problem, terminal types (ex. “0H”-“7H”) are defined for interrogators, so that only the number of authentication keys equal to the number of the terminal types are stored. Each record has the number of access permission bits equal to the number of the terminal types, and specifies terminal types, to which an access is permitted, by setting the bits ON or OFF.
摘要:
In a wireless communication system for communicating with a plurality of stations at the same point of time with the same frequency using a Space Division Multiple Access (SDMA), wireless resources are allocated by a first decision unit which evaluates performance of each station obtained when the SDMA is used and which determines periods of time to be allocated to groups of stations formed according to the SDMA technique. Using a first evaluation unit and a second evaluation unit to evaluate performance required by each station and each application, the first decision unit allocates the wireless resources to the stations. It is therefore possible that the wireless resources are efficiently allocated to the stations while preventing an event in which the wireless resources are excessive or insufficient for required quality of service.
摘要:
A contactless IC card having an antenna, a transmit/receive circuit for recovering data (clock) and electric power from a carrier signal received by the antenna, a logic circuit operated with the electric power supplied thereto from the transmit/receive circuit, and a memory. The transmit/receive circuit has a rectifier circuit for outputting data (clock) and rectifier circuits for electric power in such a manner that the carrier signal is inputted to each of the rectifier circuit for outputting data (clock) and the rectifier circuit for electric power. With this configuration, high frequency matching can be optimized separately for the rectifier circuit for outputting data (clock) and the rectifier circuit for electric power. It is also possible to separately optimize adjustments to a voltage of recovered data (clock) and a recovered supply voltage.
摘要:
A frequency-hopped mobile communication system is disclosed, in which a mobile wireless station automatically becomes a base station in accordance with the surrounding conditions, thereby automatically reconfiguring a communication network. A control frame is generated by at least one master station, and frequencies are hopped by a plurality of slave stations in accordance with the control frame. Each slave station switches the master thereof to be tracked, in accordance with the receiving conditions of the control frame and the relation between the control frame received from the master station and the status of the slave station and decides in which mode, master station or slave station, the slave station is to operate. The cells are thus automatically reconfigured.
摘要:
Disclosed is a wireless communication system capable of performing demodulation at the receiving side without substantially deteriorating BER characteristics, regardless of carrier frequency error existing among plural wireless communication systems in SDMA of uplink. The wireless communication system includes plural antennas; a MIMO processor that decomposes a reception signal the plural antennas received from plural transmitters into transmission signals transmitted from the respective transmitters; a FFT processor that carries out OFDM demodulation; and a demapping unit that obtains data from signals which were previously converted into sub-carrier signals by the FFT processor, in which the MIMO processor is installed ahead of the FFT processor for sake of the processing sequence of a receive signal, and even though a carrier frequency offset exists in the reception signal MIMO processing is performed prior to OFDM demodulation to split the reception signal from plural transmitters.