Unsolicited Channel Sounding in a Wireless Local Area Network

Patent metadata

Field	Value
Publication number	US-2016127019-A1
Application number	US-201514741419-A
Country	US
Kind code	A1
Filing date	Jun 16, 2015
Priority date	Oct 31, 2014
Publication date	May 5, 2016
Grant date	—

Abstract

A transceiver for a wireless local area network (WLAN) and the transceiver including a sounding feedback module and a sounding feedforward module. The sounding feedback module is responsive to an explicit sounding from a transmitting one of the nodes to send feedback of multiple-input multiple-output (MIMO) channel state information (CSI) derived from the channel sounding to the transmitting one of the nodes for improving subsequent transmissions. The sounding feedforward module is configured to monitor changes in CSI since the last explicit sounding based on CSI determined from the subsequent transmissions of the transmitting one of the nodes and responsive to a determination of a change in CSI above a threshold amount, to feedforward to the transmitting one of the nodes indicia of the change in CSI.

First claim

What is claimed is:

1 . A transceiver for a wireless local area network (WLAN), supporting wireless communications between associated transceiver nodes on a selected one of a plurality of communication channels:
a sounding feedback module responsive to an explicit sounding from a transmitting one of the nodes to send feedback of multiple-input multiple-output (MIMO) channel state information (CSI) derived from the channel sounding to the transmitting one of the nodes for improving subsequent transmissions; and a sounding feedforward module configured to monitor changes in CSI since the last explicit sounding based on CSI determined from the subsequent transmissions of the transmitting one of the nodes and responsive to a determination of a change in CSI above a threshold amount, to feedforward to the transmitting one of the nodes indicia of the change in CSI.

2 . The transceiver of claim 1 , further comprising:
the sounding feedforward module further configured to determine current CSI from a ubiquitous preamble field in a header portion of subsequently transmitted communication packets from the transmitting one of the nodes.

3 . The transceiver of claim 1 , further comprising:
the sounding feedforward module further configured to determine when the change in CSI exceeds a threshold amount by comparing current CSI determined from the subsequent transmissions of the transmitting one of the nodes with the CSI feedback to the transmitting one of the nodes responsive to the explicit sounding therefrom.

4 . The transceiver of claim 1 , further comprising:
the sounding feedforward module wherein the indicia of change in CSI includes at least one of: a MIMO beamsteering matrix “V”, a MIMO channel matrix “H”; and a received signal strength indicator (RSSI).

5 . The transceiver of claim 1 , further comprising:
the sounding feedforward module wherein the indicia of change in CSI includes a notification that the CSI has changed without any further information quantifying said change.

6 . The transceiver of claim 1 , further comprising:
the sounding feedforward module wherein the indicia of change in CSI includes a communication limited to quantifying only changes in at least one of the channel matrix “H” and the beamforming matrix “V” since the feedback to the last explicit sounding.

7 . The transceiver of claim 1 , operative as at least one of: a wireless access point (WAP) transceiver node and a station transceiver node of the WLAN.

8 . The transceiver of claim 1 , further comprising:
the sounding feedback module further configured to respond to an other explicit sounding from the transmitting one of the nodes, prompted by the feedforward of the indicia of the change in CSI from the sounding feedforward module.

9 . A method for unsolicited soundings of a wireless local area network (WLAN) supporting wireless communications between a wireless access point (WAP) node and a plurality of station nodes on a selected one of a plurality of communication channels, and the method comprising:
receiving an explicit channel sounding from a transmitting one of the nodes; sending feedback to the transmitting one of the nodes of multiple-input multiple-output (MIMO) channel state information (CSI) derived from the channel sounding received in the receiving act; receiving subsequent communication packets from the transmitting one of the nodes; monitoring changes in CSI since the last explicit sounding based on CSI determined from the subsequent transmissions of the transmitting one of the nodes; and feeding forward to the transmitting one of the nodes indicia of the change in monitored CSI, responsive to a determination of a change in CSI above a threshold amount.

10 . The method for unsolicited soundings of claim 9 , wherein the monitoring act further comprises:
determining current CSI from a ubiquitous preamble field in a header portion of the subsequent communication packets received from the transmitting one of the nodes.

11 . The method for unsolicited soundings of claim 9 , wherein the monitoring act further comprises:
determining when the change in CSI exceeds a threshold amount by comparing current CSI determined from the subsequent communication packets received from the transmitting one of the nodes with the CSI feedback to the transmitting one of the nodes sent in the sending act.

12 . The method for unsolicited soundings of claim 9 , wherein the indicia of change in CSI feed forward to the transmitting one of the nodes includes at least one of: a MIMO beamsteering matrix “V”, a MIMO channel matrix “H”; and a received signal strength indicator (RSSI).

13 . The method for unsolicited soundings of claim 9 , wherein the the indicia of change in CSI feed forward to the transmitting one of the nodes includes a notification that the CSI has changed without any further information quantifying said change.

14 . The method for unsolicited soundings of claim 9 , wherein the indicia of change in CSI feed forward to the transmitting one of the nodes includes a communication limited to quantifying only changes in at least one of the channel matrix “H” and the beamforming matrix “V” since the feedback to the last explicit sounding.

15 . The method for unsolicited soundings of claim 9 , further comprising:
performing the acts on at least one of: the WAP node, and one or more of the plurality of station nodes.

16 . The method for unsolicited soundings of claim 9 , further comprising:
repeating the first receiving act and the sending act responsive to an other explicit sounding from the transmitting one of the nodes, prompted by the feedforward of the indicia of the change in CSI to the transmitting one of the nodes in the feed forward act.

17 . A non-transient computer readable medium containing program instructions for causing a computer to perform the method of:
receiving an explicit channel sounding from a transmitting one of the nodes; sending feedback to the transmitting one of the nodes of multiple-input multiple-output (MIMO) channel state information (CSI) derived from the channel sounding received in the receiving act; receiving subsequent communication packets from the transmitting one of the nodes; monitoring changes in CSI since the last explicit sounding based on CSI determined from the subsequent transmissions of the transmitting one of the nodes; and feeding forward to the transmitting one of the nodes indicia of the change in monitored CSI, responsive to a determination of a change in CSI above a threshold amount.

18 . The non-transient computer readable medium containing program instructions of claim 17 for causing a computer to perform the method of:
determining current CSI from a ubiquitous preamble field in a header portion of the subsequent communication packets received from the transmitting one of the nodes.

19 . The non-transient computer readable medium containing program instructions of claim 17 for causing a computer to perform the method of:
determining when the change in CSI exceeds a threshold amount by comparing current CSI determined from the subsequent communication packets received from the transmitting one of the nodes with the CSI feedback to the transmitting one of the nodes sent in the sending act.

Assignees

• Quantenna Communications Inc

Inventors

• Schelstraete Sigurd
• Dehghan Hossein
• Heidari Sam
• Amiri Bahador

Classifications

• H04W64/003

  locating network equipment · CPC title

• H04B7/0626

  Channel coefficients, e.g. channel state information [CSI] · CPC title

• H04B7/0617

  for beam forming · CPC title

• H04B7/0645

  Variable feedback · CPC title

• H04B7/0634

  Antenna weights or vector/matrix coefficients · CPC title