Apparatus and method for sounding wireless channel
View Patent ↗A method and system for improving the accuracy of phase and frequency offset during multiple in multiple out (MIMO) channel estimation in a sounding procedure. The improved phase and frequency offset process selects resource allocation unit configuration to ensure a minimum pilot density from the available operation modes. A method for reducing the data in the feedback matrix of the sounding procedure correlates the long training frame (LTF) and number of groups (Ng) between the sounding frame and the feedback to improve efficiency in the amount of feedback that is returned.
1. A non-transitory computer-readable medium having stored therein computer code, which when executed by a networking device functioning as a beamformer in a wireless local area network (WLAN), cause the networking device to perform a set of operations to improve a sounding procedure where a steering matrix or a compressed beamforming report is utilized by the beamformer using feedback from at least one beamformee, the steering matrix or compressed beamforming report to determine a spatial path for transmission from the beamformer to a set of beamformees in the WLAN, the set of operations comprising:
selecting, by the beamformer, a bandwidth for a sounding frame used to perform the sounding procedure;
generating, by the beamformer, the sounding frame at the selected bandwidth using a mode of operation from a plurality of modes of operation, wherein each mode of operation corresponds to a frame format and the mode of operation used to generate the sounding frame has a minimum pilot tone density amongst frame formats of the plurality of modes of operation with the selected bandwidth;
and
transmitting the sounding frame to the set of beamformees.
2. The transitory computer-readable medium of claim 1 , wherein the plurality of modes of operation includes a single user mode of operation at the selected bandwidth and a multiuser mode of operation at the selected bandwidth for transmissions using a High-Efficiency Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU).
3. The non-transitory computer-readable medium of claim 1 , wherein the plurality of modes of operation includes a first mode of operation at the selected bandwidth with a first resource unit allocation and a second mode of operation at the selected bandwidth with a second resource unit allocation.
4. The non-transitory computer-readable medium of claim 3 , wherein the first resource unit allocation includes multiple resource units and the second resource unit allocation includes a single resource unit,
wherein the mode of operation used to generate the sounding frame is the second mode of operation.
5. The non-transitory computer-readable medium of claim 4 , wherein the multiple resource units are each portions of the selected bandwidth and the single resource unit is the entire selected bandwidth.
6. The non-transitory computer-readable-medium of claim 4 , having further instructions stored therein to cause the networking device to perform additional operations comprising:
transmitting, by the beamformer, a data frame to two or more of the beamformees using the first mode of operation.
7. The non-transitory computer-readable medium of claim 1 , wherein the plurality of modes of operation are modes which the beamformer is permitted to transmit within the WLAN.
8. The non-transitory computer-readable medium of claim 1 , wherein the sounding frame is a null data packet (NDP) frame.
9. A method implemented by a beamformer in a wireless local area network (WLAN), the method to improve a sounding procedure where a steering matrix or a compressed beamforming report is utilized by the beamformer using feedback from at least one beamformee, the steering matrix or compressed beamforming report to determine a spatial path for transmission from the beamformer to a set of beamformees in the WLAN, the method comprising:
selecting, by the beamformer, a bandwidth for a sounding frame used to perform the sounding procedure;
generating, by the beamformer, the sounding frame at the selected bandwidth using a first mode of operation corresponding to a first frame format, wherein the first mode of operation is within a set of modes of operation that the beamformer is permitted to utilize in the WLAN, wherein each mode of operation in the set of modes of operation corresponds to a separate frame format and the first frame format has a minimum pilot tone density amongst the frame formats associated with the modes of operation in the set of modes of operation with the selected bandwidth; and
transmitting the sounding frame to the set of beamformees.
10. The method of claim 9 , wherein the set of modes of operation includes a single user mode of operation at the selected bandwidth and a multiuser mode of operation at the selected bandwidth for transmissions using a High-Efficiency Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU).
11. The method of claim 9 , wherein the set of modes of operation includes the first mode of operation at the selected bandwidth with a first resource unit allocation and a second mode of operation at the selected bandwidth with a second resource unit allocation.
12. The method of claim 11 , wherein the first resource unit allocation includes a single resource unit and the second resource unit allocation includes multiple resource units.
13. The method of claim 12 , wherein the multiple resource units are each portions of the selected bandwidth and the single resource unit is the entire selected bandwidth.
14. The method of claim 12 , further comprising:
transmitting, by the beamformer, a data frame to two or more of the beamformees using the second mode of operation.
15. The method of claim 9 , wherein the sounding frame is a null data packet (NDP) frame.
16. An apparatus functioning as a beamformer in a wireless local area network (WLAN), the apparatus to improve a sounding procedure where a steering matrix or a compressed beamforming report is utilized by the beamformer using feedback from at least one beamformee, the steering matrix or compressed beamforming report to determine a spatial path for transmission from the beamformer to a set of beamformees in the WLAN, the apparatus comprising:
a Radio Frequency (RF) transceiver;
a non-transitory machine-readable medium having stored therein an enhanced sounding procedure module; and
a set of one or more processors coupled to the non-transitory machine-readable medium, the set of one or more processors configured to execute the enhanced sounding procedure module, the enhanced sounding procedure module to select a bandwidth for a sounding frame used to perform the sounding procedure, to generate the sounding frame using a first mode of operation corresponding to a first frame format, wherein the first mode of operation is within a set of modes of operation that the beamformer is permitted to utilize in the WLAN, wherein each mode of operation in the set of modes of operation corresponds to a separate frame format and the first frame format has a minimum pilot tone density amongst the frame formats associated with the modes of operation in the set of modes of operation with the selected bandwidth, and to transmit the sounding frame to the set of beamformees.
17. The apparatus of claim 16 , wherein the set of modes of operation includes a single user mode of operation at the selected bandwidth and a multiuser mode of operation at the selected bandwidth for transmissions using a High-Efficiency Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU).