Abstract:
An adaptive frequency selective baseband communications method using orthogonal codes includes: a communications testing step of performing communications by using one of a plurality of codes each having a different frequency band; a proper code selecting step of selecting a proper code by using a correlation value of a plurality of codes included in test data transmitted in the communications testing step; a communications performing step of performing communications by using the proper code; and a feedback step of newly selecting a proper code by using the correlation value of the plurality of codes included in the test data transmitted in the communications performing step if a pre-set time duration has lapsed or if a reception error of more than a pre-set reference occurs, and performing the communications performing step again, wherein the test data transmitted in the communications testing step and the communications performing step includes a plurality of codes each having a different frequency band.
Abstract:
Provided are modulation and demodulation methods and apparatuses using a frequency selective baseband. The frequency modulation method includes: generating a plurality of subgroups by dividing 2N (N is a real number) spread codes used for frequency spreading into 2M (M
Abstract:
A technique for simultaneously acquiring vehicle identification information and speed information of an RFID tag-attached vehicle by calculating the vehicle speed by using a Doppler shift value extracted from transmission and reception signals between the RFID tag and the RFID reader is disclosed. A method for measuring a vehicle speed by using an RFID reader installed right up on the road or at the roadside includes: transmitting a continuous wave; receiving a reflected wave with respect to the continuous wave from an RFID tag attached to a vehicle which has received the continuous wave; extracting a Doppler shift value from the continuous wave and the reflected wave; and calculating the speed of the vehicle by using the Doppler shift value.
Abstract:
Provided are a human body sound transmission system and a method using single sound source. The human body sound transmission system includes a first transmission block for transmitting a combined signal of a first high frequency signal and a sound signal through a human body; and a second transmission block for transmitting a second high frequency signal having the same frequency as the first high frequency signal through the human body, to thereby recover the sound signal by destructing interference in a ear region of a user.
Abstract:
Provided are a digital communication system using frequency selective baseband and a method thereof. A transmitter of the digital communication system, includes: a preamble/header transmission processing unit for spreading a preamble for frame synchronization and a header including data information; a data transmission processing unit for spreading data by using spread codes having dominant frequency in a desired frequency band, i.e., frequency selective spread codes; and a multiplexer for multiplexing the spreaded preamble and the spreaded header from the preamble/header transmission processing unit and the frequency selective spreaded data from the data transmission processing unit and transmitting the multiplexed signal in digital.
Abstract:
In an apparatus for a TFCI mapping in a wireless communication mobile station, and a method thereof, the apparatus includes an encoding unit for encoding a TFCI transmitted from a main control unit as a CPU; a TFCI mapping unit for generating necessary control parameter and a TFCI code by using a signal encoded by the encoding unit and a signal transmitted from the CPU; and a CPU for controlling the encoding unit and the mapping unit.
Abstract:
A frequency selective modulation apparatus and method using re-spreading codes are disclosed. The frequency selective modulation apparatus includes: a serial-to-parallel converter receiving transmission data and performing serial-to-parallel conversion on the transmission data at a pre-set ratio; one or more sub-frequency selective spreaders selecting one spreading code by using data bits received from the serial-to-parallel converter; a majority value selection unit selecting a majority value from one or more spreading codes which have been selected by each of the one or more of the sub-frequency selective spreaders; and a first XOR logic circuit XORing an output of the majority value selection unit and a re-spreading code Wn to re-spread a frequency selective baseband to a frequency selective passband.
Abstract:
A method and apparatus for communicating a sound wave is provided. The apparatus includes: a sound wave converter converting a sound wave signal transmitted from a counter apparatus through the human body into an electrical signal when the sound wave is transmitted from the counter apparatus through the human body and converting an electrical signal on data to be output to the counter apparatus into a sound wave; a data processor receiving the converted electrical signal from the sound wave converter and transmitting an electrical signal on the data to be output to the sound wave converter when the data to be output exists; and a switch connected between the sound wave converter and the data processor, the switch transmitting the converted electrical signal to the data processor and transmitting the electrical signal on the data to be output to the sound wave converter. Accordingly, it is possible to efficiently transmit a signal with a low loss of sound wave signal. Thus, it is possible to simply construct communication hardware at a low price.
Abstract:
Provided are a human body communication apparatus for non-contact communications using a frequency-selective baseband and a human body communication method for non-contact communications in the same. The human body communication apparatus may be useful to perform stable communications between users by reducing interference induced from other communication apparatuses without affecting interference between the users since data are transmitted/received between communication apparatuses adjacent to a human body by spreading and despreading the data using only spreading codes of a limited frequency band (frequency-selective baseband) in which an inductive electromagnetic field formed by an antenna shows the most effective characteristics.
Abstract:
Provided is a method of generating and detecting a preamble that may significantly increase accuracy of frame synchronization while avoiding a low frequency domain having great noise power and minimizing hardware complexity and power consumption in a communication system of a digital direct transmission scheme applicable to human body communication. A method of generating a preamble according to an exemplary embodiment of the present disclosure includes: generating a first pseudo noise code and a second pseudo noise code that are different from each other; generating a plurality of same first sub preambles by line-coding the first pseudo noise code; and generating a second sub preamble behind the plurality of first sub preambles by line-coding the second pseudo noise code.