Wireless communication system, wireless communication apparatus and wireless communication method
A wireless communication system which performs data transmission using spatially multiplexed streams from a first terminal including N antennas to a second terminal including M antennas (N is an integer of 2 or more and M is an integer of 1 or more) is disclosed. The system includes notifying means, training means, channel matrix estimation means, beamforming information feedback means, transmission weight matrix setting means, and beamforming means.
1. A receiving device for wireless communication, the receiving device comprising:
processing circuitry configured to:
transmit a channel estimation capability including a maximum number of space time streams, the channel estimation capability being included in a beamforming capability field of a management frame defined in wireless network standard IEEE 802.11;
estimate a channel matrix;
transmit feedback information generated based at least in part on the estimated channel matrix; and
receive a data signal by explicit feedback beamforming using the transmission weight matrix generated based at least in part on the feedback information.
2. The receiving device of claim 1 , wherein the beamforming capability field is included in a HT (high throughput) capabilities element defined in wireless network standard IEEE 802.11.
3. The receiving device of claim 2 , wherein the HT capabilities element is present in a management frame.
4. The receiving device of claim 3 , wherein the management frame includes a beacon signal, a measure pilot, an association response, a re-association response, and/or a probe response.
5. The receiving device of claim 1 , wherein the maximum number of space time streams indicates a number of columns of a MIMO (multiple-input multiple output) channel matrix for the wireless communication.
6. The receiving device of claim 5 , wherein the channel state information is estimated as a channel state information matrix, a number of columns of the channel state information matrix being equal to or less than the number of columns of MIMO channel matrix.
7. The receiving device of claim 1 , further configured to:
receive a sounding data unit, the received sounding data unit being used to estimate the channel matrix.
8. The receiving device of claim 7 , wherein a length of the sounding data unit is equal to or less than a number indicated by the channel estimation capability.
9. The receiving device of claim 7 , wherein the sounding data unit is generated as a staggered sounding packet.
10. The receiving device of claim 1 , wherein the channel estimation capability is represented by two bits, the two bits being located adjacent to a bit field including an information of maximum beamformer capability.
11. The receiving device of claim 1 , wherein the beamforming capability field further includes both implicit beamforming capability information and explicit beamforming capability information.
12. The receiving device of claim 1 , further comprising:
a plurality of antennas configured to transmit or receive signals including the channel estimation capability.
13. The receiving device of claim 12 , wherein a number of the plurality of antennas is two or three.
14. The receiving device of claim 12 , further comprising:
a plurality of digital filters configured to perform band limitation, a number of the plurality of digital filters being equal to a number of the plurality of antennas.
15. A mobile receiving apparatus for wireless communication, the mobile receiving apparatus comprising:
a plurality of antennas; and
processing circuitry configured to:
transmit a channel estimation capability including a maximum number of space time streams, the channel estimation capability being included in a beamforming capability field of a management frame defined in wireless network standard IEEE 802.11;
estimate a channel matrix;
transmit feedback information generated based at least in part on the estimated channel matrix; and
receive a data signal by explicit feedback beamforming using the transmission weight matrix generated based at least in part on the feedback information.
16. The mobile receiving apparatus of claim 15 , wherein the mobile receiving apparatus is a mobile telephone.
17. The mobile receiving apparatus of claim 15 , wherein the number of the plurality of antennas is two.
18. The mobile transmitting apparatus of claim 15 , wherein the number of the plurality of antennas is three.
19. A receiving method for wireless communication, the receiving method comprising:
transmitting a channel estimation capability including a maximum number of space time streams, the channel estimation capability being included in a beamforming capability field of a management frame defined in wireless network standard IEEE 802.11;
estimating a channel matrix;
transmitting feedback information generated based at least in part on the estimated channel matrix; and
receiving a data signal by explicit feedback beamforming using the transmission weight matrix generated based at least in part on the feedback information.
20. The receiving method of claim 19 , wherein the beamforming capability field is included in a HT (high throughput) capabilities element defined in wireless network standard IEEE 802.11.
21. The receiving method of claim 20 , wherein the HT capabilities element is present in a management frame.
22. The receiving method of claim 21 , wherein the management frame includes a beacon signal, a measure pilot, an association response, a re-association response, and/or a probe response.
23. The receiving method of claim 19 , wherein the maximum number of space time streams indicates a number of columns of a MIMO (multiple-input multiple output) channel matrix for the wireless communication.
24. The receiving method of claim 23 , wherein the channel state information is estimated as a channel state information matrix, a number of columns of the channel state information matrix being equal to or less than the number of columns of MIMO channel matrix.
25. The receiving method of claim 19 , further including:
receiving a sounding data unit, the received sounding data unit being used to estimate the channel matrix.
26. The receiving method of claim 25 , wherein a length of the sounding data unit is equal to or less than a number indicated by the channel estimation capability.
27. The receiving method of claim 25 , wherein the sounding data unit is generated as a staggered sounding packet.
28. The receiving method of claim 19 , wherein the channel estimation capability is represented by two bits, the two bits being located adjacent to a bit field including an information of maximum beamformer capability.
29. The receiving method of claim 19 , wherein the beamforming capability field further includes both implicit beamforming capability information and explicit beamforming capability information.