1. A wireless communication system which exchanges data between an access point and plural stations, wherein at least one of said stations comprises:
a received power measurement unit which measures received power when data transmitted from said access point is received;
a received data type detection unit which detects the type of the received data;
a beam gain estimation unit which determines the presenceabsence of directional beam control in said access point, on the basis of, the received power measured by said received power measurement unit, and the received data type detected by said received data type detection unit; and
a transmitter power control unit which controls transmitting power for transmitting data to said access point, in accordance with the result of the determination by said beam gain estimation unit.
2. A system according to claim 1, wherein said received data type detection unit detects whether received data are broadcast frame data or unicast frame data.
3. A system according to claim 1, wherein said beam gain estimation unit determines that space division multiple access (SDMA) is applicable at said access point, when the level of the directional beam is larger or equal to a predetermined level.
4. A system according to claim 1, further comprising:
a transmitted power detection unit which detects transmitted power when said access point transmits data.
5. A wireless communication system which exchanges data between an access point and plural stations by CSMA (Carrier Sense Multiple Access), wherein at least one of said stations comprises:
a received power measurement unit which measures received power when data transmitted from said access point is received;
a received data type detection unit which detects the type of the received data;
a beam gain estimation unit which determines the presenceabsence of directional beam control in said access point, on the basis of the received power measured by said received power measurement unit, and the received data type detected by said received data type detection unit;
a transmitter power control unit which controls transmitting power for transmitting data to said access point, in accordance with the result of the determination by said beam gain estimation unit; and
a carrier sense control unit which controls the carrier sense level of said station in accordance with the result of the determination by said beam gain estimation unit.
6. A system according to claim 5, wherein said received data type detection unit detects whether received data are broadcast frame data or unicast frame data.
7. A system according to claim 5, further comprising:
a transmitted power detection unit which detects transmitted power when said access point transmits data.
8. A wireless communication system which exchanges data between an access point and plural stations, wherein at least one of said stations comprises:
a received power measurement unit which measures the received power of the first data which are broadcast from said access point, and measures the received power of the second data which are unicast from said access point to said station;
a beam gain estimation unit which determines the presenceabsence of directional beam control in said access point, on the basis of the first and second received powers measured by said received power measurement unit; and
a transmitting power control unit which controls transmitting power for transmitting data to said access point, when said beam gain estimation unit determines that said access point is performing directional beam control.
9. A system according to claim 8, wherein when said beam gain estimation unit determines that said access point is performing directional beam control, said transmitting power control unit sets the transmitting power to transmit data to said access point at the minimum necessary power receivable by said access point.
10. A system according to claim 8, wherein when determining that said access point is performing directional beam control, said beam gain estimation unit further checks whether space division multiple access is applicable at said access point, and when said beam gain estimation unit determines that said access point is performing directional beam control, and that space division multiple access is applicable at said access point, said transmitting power control unit sets the transmitting power to transmit data to said access point at the minimum necessary power receivable by said access point.
11. A system according to claim 8, further comprising:
a transmitted power detection unit which detects transmitted power when said access point transmits the first data, and detects transmitted power when said access point transmits the second data.
12. A wireless communication system which exchanges data between an access point and plural stations by CSMA (Carrier Sense Multiple Access), wherein at least one of said stations comprises:
a received power measurement unit which measures the received power of the first data which are broadcast from said access point, and measures the received power of the second data which are unicast from said access point to said station;
a beam gain estimation unit which determines the presenceabsence of directional beam control in said access point, on the basis of the first and second received powers measured by said received power measurement unit;
a transmitting power control unit which controls transmitting power to transmit data to said access point, when said beam gain estimation unit determines that said access point is performing directional beam control; and
a carrier sense control unit which controls the carrier sense level of said station in accordance with the result of the determination by said beam gain estimation unit.
13. A system according to claim 12, wherein when said beam gain estimation unit determines that said access point is performing directional beam control, said carrier sense control unit raises the carrier sense level of said station to such an extent that the carrier sense function does not degrade.
14. A system according to claim 12, wherein
when determining that said access point is performing directional beam control, said beam gain estimation unit further checks whether space division multiple access is applicable at said access point, and
when said beam gain estimation unit determines that said access point is performing directional beam control, and that space division multiple access is applicable at said access point, said carrier sense control unit raises the carrier sense level of said station to such an extent that the carrier sense function does not degrade.
15. A system according to claim 12, further comprising:
a transmitted power detection unit which detects transmitted power when said access point transmits the first data, and detects transmitted power when said access point transmits the second data.
16. A wireless station which exchanges data with an access point, comprising:
a received power measurement unit which measures the received power of the first data which are broadcast from said access point, and measures the received power of the second data which are unicast from said access point to said station;
a beam gain estimation unit which determines the presenceabsence of directional beam control in said access point, on the basis of the first and second received powers measured by said received power measurement unit; and
a transmitting power control unit which controls transmitting power for transmitting data to said access point, when said beam gain estimation unit determines that said access point is performing directional beam control.
17. A station according to claim 16, wherein when said beam gain estimation unit determines that said access point is performing directional beam control, said transmitting power control unit sets the transmitting power to transmit data to said access point at the minimum necessary power receivable by said access point.
18. A station according to claim 16, wherein when determining that said access point is performing directional beam control, said beam gain estimation unit further checks whether space division multiple access is applicable at said access point, and
when said beam gain estimation unit determines that said access point is performing directional beam control, and that space division multiple access is applicable at said access point, said transmitting power control unit sets the transmitting power to transmit data to said access point at the minimum necessary power receivable by said access point.
19. A station according to claim 16, further comprising:
a transmitted power detection unit which detects transmitted power when said access point transmits the first data, and detects transmitted power when said access point transmits the second data.
20. A wireless station which exchanges data with an access point by CSMA (Carrier Sense Multiple Access), comprising:
a received power measurement unit which measures the received power of the first data which are broadcast from said access point, and measures the received power of the second data which are unicast from said access point to said station;
a beam gain estimation unit which determines the presenceabsence of directional beam control in said access point, on the basis of the first and second received powers measured by said received power measurement unit, and the first and second transmitted powers detected by said transmitted power detection unit;
a transmitting power control unit which controls transmitting power for transmitting data to said access point, when said beam gain estimation unit determines that said access point is performing directional beam control; and
a carrier sense control unit which controls the carrier sense level of said station in accordance with the result of the determination by said beam gain estimation unit.
21. A wireless station according to claim 20, further comprising:
a transmitted power detection unit which detects transmitted power when said access point transmits the first data, and detects transmitted power when said access point transmits the second data.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A transmitter, comprising:
an image data generation unit generating image frames including image data regarding an obtained image;
a transmission frame generation unit receiving the image frames to generate a transmission frame; and
transmitting electrodes transmitting the transmission frame,
wherein the transmission frame includes a plurality of control frames used for selecting pairs of receiving electrodes in a receiver and a plurality of data frames including the image frames.
2. The transmitter of claim 1, wherein each of the plurality of control frames includes:
a first preamble used to synchronize the frames and select the receiving electrodes, a first header differentiating frame types,
frame information including information on the image frames; and
a switching time section for providing time required for electrode switching in the receiver, and
each of the plurality of data frames includes:
a second preamble synchronizing the frames,
a second header differentiating the frame types; and
at least a portion of the image frames.
3. The transmitter of claim 2, wherein the number of plurality of control frames is determined by the number of receiving electrodes in the receiver.
4. The transmitter of claim 2, wherein the transmission frame generation unit includes:
a data modulation unit modulating the image frames according to a preset modulation scheme;
a preamble generation unit generating the first and second preambles;
a header generation unit generating the first and second headers;
a frame information generation unit generating the frame information; and
a multiplexer multiplexing the modulated image frame, the first and second preambles, the first and second headers, and the frame information and the switching time section to generate the transmission frame.
5. A receiver in a human communication system, comprising:
a plurality of receiving electrodes receiving a transmission frame including a plurality of control frames and a plurality of data frames;
first and second switches connected with the plurality of receiving electrodes;
a switching control unit controlling a switching of the first and second switches so as to selectively connect the plurality of receiving electrodes with the first and second switches in response to each control frame according to a predetermined rule when each of the plurality of control frames is input;
a signal processing unit performing signal processing on the transmission frame output from the first and second switches;
a preamble detection unit detecting the first preamble from each of the plurality of control frames included in the signal-processed transmission frame to generate preamble correlation values for the first preamble; and
a correlation value processing unit controlling the switching control unit so as to select pairs of final receiving electrodes among the plurality of receiving electrodes based on the preamble correlation values.
6. The receiver of claim 5, wherein the preamble correlation value represents correlation of data obtained by comparing each of the detected first preambles with a predetermined reference preamble for each bit.
7. The receiver of claim 6, wherein the correlation processing unit selects two receiving electrodes corresponding to the first preamble having a highest absolute value between the predetermined reference correlation value and the preamble correlation value as the pairs of final receiving electrodes.
8. The receiver of claim 5, wherein each of the plurality of control frames includes:
the first preamble used to synchronize the frames and select the pairs of final receiving electrodes;
a first header differentiating frame types;
frame information including information on the image frames; and
a switching time section for providing time required for switching control in the switching control unit, and
each of the plurality of data frames includes:
a second preamble synchronizing the frames;
a second header differentiating the frame types; and
at least a portion of the image frames.
9. The receiver of claim 8, wherein the number of plurality of control frames is determined by the number of the plurality of receiving electrodes.
10. The receiver of claim 8, further comprising:
a demultiplexer demultiplexing the signal-processed transmission frame;
a header processing unit demodulating a header section in an output from the demultiplexer;
a data demodulation unit demodulating the image frames in the output from the demultiplexer when the frame type is a data frame as a result of determining the header demodulated in the header processing unit; and
an image data processing unit processing the demodulated image frame.
11. A method for transmitting data used for a human body communication system, comprising:
generating image frames including image data regarding an obtained image;
generating a transmission frame including the image frames; and
transmitting the transmission frame through transmitting electrodes;
wherein the transmission frame includes a plurality of control frames used for selecting pairs of receiving electrodes in a receiver and a plurality of data frames including the image frames.
12. The method of claim 11, wherein each of the plurality of control frames includes:
a first preamble used to synchronize the frames and select the receiving electrodes;
a first header differentiating frame types;
frame information including information on the image frames; and
a switching time section for providing time required for electrode switching in the receiver, and
each of the plurality of data frames includes:
a second preamble synchronizing the frames;
a second header differentiating the frame types; and
at least a portion of the image frames.
13. The method of claim 12, wherein the number of plurality of control frames is determined by the number of receiving electrodes in the receiver.
14. The method of claim 12, wherein the generating of the transmission frame includes:
modulating the image frame according to a preset modulation scheme;
generating the first and second preambles;
generating the first and second headers;
generating the frame information; and
multiplexing the modulated image frame, the first and second preambles, the first and second headers, and the frame information and the switching time section to generate the transmission frame.
15. A method for receiving data used in a human body communication system, comprising:
receiving a transmission frame including a plurality of control frames and a plurality of data frames through a plurality of receiving electrodes;
controlling, by a switching control unit, a switching of a first and second switches so as to selectively connect the plurality of receiving electrodes with the first and second switches in response to each control frame according to a predetermined rule when each of the plurality of control frames is input;
performing, by a signal processing unit, signal processing on the transmission frame output from the first and second switches;
detecting, by a preamble detection unit, the first preamble from each of the plurality of control frames included in the signal-processed transmission frame to generate preamble correlation values for the first preamble; and
controlling, by a correlation value processing unit, the switching control unit so as to select pairs of final receiving electrodes among the plurality of receiving electrodes based on the preamble correlation values.
16. The method of claim 15, wherein the preamble correlation value represents correlation of data obtained by comparing each of the first preambles with a predetermined reference preamble for each bit.
17. The method of claim 16, wherein two receiving electrodes corresponding to the first preamble having a highest absolute value between the predetermined reference correlation value and the preamble correlation value are selected as the pairs of final receiving electrodes.
18. The method of claim 15, wherein each of the plurality of control frames includes:
a first preamble used to synchronize the frames and select the final receiving electrodes,
a first header differentiating frame types,
frame information including information on the image frames; and
a switching time section for providing time required for switching control in the switching control unit, and
each of the plurality of data frames includes:
a second preamble synchronizing the frames;
a second header differentiating the frame types; and
at least a portion of the image frames.
19. The method of claim 18, wherein the number of plurality of control frames is determined by the number of the plurality of receiving electrodes.