1. A noise removal apparatus to receive a signal comprising a first and a second voice signal and including a first microphone mounted close to a speaker and at least one second microphone spaced a predetermined distance from the first microphone, comprising:
a first and second frequency domain conversion units to convert the first and the second voice signal mixed with noise to frequency domain signals when the first and second voice signals are input from each of the microphones;
a bin comparator to determine a voice section and a noise section using each of the converted first and second voice signals and to determine whether a current section of the signal is the voice section or the noise section using each of the converted first and second voice signals;
a subtraction unit to subtract a voice signal component from the converted second voice signal;
a noise clustering unit to determine, based on a result of the determination by the bin comparator, the noise type of the second voice signal, in which the voice signal component has been subtracted in the noise section; and
a noise removal algorithm unit to remove noise corresponding to the noise type from the converted first voice signal.
2. The noise removal apparatus of claim 1, wherein the subtraction unit subtracts the voice signal component, which corresponds to a difference ratio of voice signals in consideration of a distance between two microphones, from the converted second voice signal.
3. The noise removal apparatus of claim 1, wherein the bin comparator increases a count value each time frequency data of the first voice signal is bigger than frequency data of the second voice signal multiplied by a margin value, performs dimension comparison between the data in each frequency bin, and then determines, using a count value based on a result of the comparison, if the current section is a voice section or a noise section.
4. The noise removal apparatus of claim 1, wherein the noise clustering unit classifies noise into at least one type through clustering over the noise section, calculates a similarity level between basic noise and the classified type of noise, and determines noise of a highest level in the calculated similarity level.
5. The noise removal apparatus of claim 4, wherein the basic noise corresponds to noise updated through a previous clustering.
6. The noise removal apparatus of claim 1, further comprising: a remaining noise eliminator for removing remaining noise from the noise-removed signal; and a time domain conversion unit for converting the remaining noise-removed signal into a time domain signal.
7. A noise removal method by a noise removal apparatus that receives a signal comprising a first and a second voice signal and that includes a first microphone mounted close to a speaker and at least one second microphone spaced a predetermined distance from the first microphone, the method comprising:
converting the first and the second voice signal mixed with noise to frequency domain signals when the first and second voice signals are input from each of the microphones;
determining a voice section and a noise section using each of the converted first and second voice signals and determining if a current section of the signal is the voice section or the noise section;
subtracting a voice signal component from the converted second voice signal;
based on a result of the determination, determining the noise type of the second voice signal, in which the voice signal component has been subtracted in the noise section; and
removing noise corresponding to the noise type from the first voice signal.
8. The noise removal method of claim 7, wherein the step of determining if the current section is a voice section or a noise section comprises the step of performing the section determination by using the each converted signal.
9. The noise removal method of claim 7, wherein the step of determining if the current section is a voice section or a noise section comprises the steps of: increasing a count value each time frequency data of the first voice signal is bigger than frequency data of the second voice signal multiplied by a margin value; and performing dimension comparison between the data in each frequency bin and then determining, by using a count value according to a result of the comparison, if the current section is a voice section or a noise section.
10. The noise removal method of claim 7, wherein the step of determining the noise type comprises the steps of: classifying noise into at least one type through clustering over the noise section; calculating a similarity level between basic noise and the classified type of noise; and determining noise of a highest level in the calculated similarity level.
11. The noise removal method of claim 10, wherein the basic noise corresponds to noise updated through previous clustering.
12. The noise removal method of claim 7, further comprising the steps of: removing remaining noise from the noise-removed signal; and converting the remaining noise-removed signal into a time domain signal.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A quality of service (QoS) control system used for a radio transmitterreceiver, comprising:
a QoS control unit for supplying the modulator of said radio transmitterreceiver with the transmission data in the order taking the QoS into consideration; and
a determining unit connected to said QoS control unit for determining whether the QoS control operation of the transmission data is required or not in accordance with the information transmission conditions in the radio section;
wherein the QoS control operation of the transmission data by said QoS control unit is performed selectively in accordance with the information transmission conditions in the radio section.
2. A QoS control system according to claim 1,
wherein said QoS control unit has a first operation mode for outputting said transmission data in the order of input and a second operation mode for outputting said transmission data in the order taking the QoS into consideration, said first and second operation modes being switchable to each other in accordance with the information transmission conditions in said radio section.
3. A QoS control system according to claim 2,
wherein said QoS control unit includes a comparator for comparing said information transmission rate for said radio section with a predetermined threshold value, said QoS control unit being switched to said second operation mode in the case where said information transmission rate for said radio section is lower than a predetermined threshold value, said QoS control unit being switched to said first operation mode in the case where said information transmission rate for said radio section is not lower than said predetermined threshold value.
4. A QoS control system according to claim 3,
wherein said QoS control unit has a queue unit for outputting said transmission data in the order of input in said first operation mode.
5. A QoS control system according to claim 3,
wherein said QoS control unit has a class-wise queue unit for setting the transmission data in a queue in accordance with the class of said transmission data in said second operation mode.
6. A QoS control system according to claim 5,
wherein said QoS control unit includes a class-wise band assignment table for setting a guarantee band for each class and a read control unit for reading the transmission data from said class-wise queue unit in accordance with said class-wise band assignment table.
7. A QoS control system according to claim 1,
wherein said information transmission rate for said radio section is obtained from the information on specific bits contained in the received data.
8. A QoS control system according to claim 1,
wherein said QoS control unit has a plurality of QoS control modes, and
wherein the QoS control mode applicable to the transmission data is switched between said plurality of said QoS control modes in accordance with the information transmission rate for said radio section.
9. A QoS control system according to claim 8,
wherein said QoS control unit has a QoS control mode table for defining the relation between the range of the transmission rate for said radio section and the QoS control mode applicable to the transmission data, and
wherein said QoS control mode applicable to the transmission data is determined in accordance with the information transmission rate for the radio section with reference to said QoS control mode table.
10. A QoS control system according to claim 8,
wherein said QoS control unit has a classification table showing the correspondence between the class and a specific QoS control mode defined by said QoS control mode table, and
wherein said classification table defines the class of each transmission data corresponding to the value of specific header information contained in said transmission data, and
wherein said QoS control unit determines the class of the transmission data in said specific QoS control mode with reference to said classification table.
11. A QoS control method for a radio transmitterreceiver, comprising:
a first step of determining whether the QoS control of the transmission data is required or not in accordance with the information transmission conditions in the radio section;
a second step of supplying the transmission data to the modulator of said radio transmitterreceiver in the order taking the QoS into consideration in the case where said QoS control operation is required; and
a third step of supplying the transmission data to said modulator in the order of input in the case where said QoS control operation is not required.
12. A QoS control method for a radio transmitterreceiver according to claim 11,
wherein said second step includes the steps of determining the class of each of said transmission data, setting said transmission data in a class-wise queue corresponding to a determined class, and reading the transmission data from said class-wise queue in accordance with a class-wise band assignment table with a guaranteed band set for each class.
13. A radio transmitterreceiver comprising:
an adaptive modulation-type transmission unit connected to an antenna; and
a receiving unit connected to said antenna;
wherein said adaptive modulation-type transmission unit includes:
a high frequency unit connected to said antenna;
a modulation unit connected to said high-frequency unit;
a radio frame coding unit connected to said modulation unit for converting the transmission data into a format of a modulation scheme corresponding to the propagation path conditions in the radio section; and
a QoS control unit for supplying the transmission data to said radio frame coding unit in order taking the quality of service (QoS) into consideration.
14. A radio transmitterreceiver according to claim 13, further comprising a propagation path estimation unit for estimating the conditions of the propagation path for the radio section from the signal received by said receiving unit.
15. A radio transmitterreceiver according to claim 14, further comprising a modulation-type selecting unit connected to said propagation path estimation unit for selecting one of a plurality of modulation schemes.
16. A radio transmitterreceiver according to claim 15,
wherein said plurality of the modulation schemes include 64 QAM, 16 QAM, QPSK and BPSK.
17. A radio transmitterreceiver according to claim 13,
wherein said receiving unit includes means for extracting the information on the modulation scheme of the received data from said received data.
18. A fixed wireless access (FWA) system comprising:
a radio base station; and
a plurality of subscriber stations adapted to communicate with said base station by radio;
wherein selected one of said radio base station and said subscriber stations includes a radio transmitterreceiver according to claim 13.