Beamformer solicited sounding
Example implementations are directed to methods and systems employing a solicited sounding protocol that includes an efficient communication sequence for operating a wireless transceiver transmitting a sounding trigger to one or more beamformees via a forward channel, receiving at least one dedicated training signal from the one or more beamformees via a reverse channel in response to the sounding trigger, and for each of the received dedicated training signal. The method also includes estimating forward CSI derived based on the dedicated training signal from an associated beamformee; and where subsequent packets are precoded with precoding derived from the forward CSI for transmission to the associated beamformee via the forward channel. Example aspects including scheduling multiple dedicated training signals from one or more beamformees based on a single sounding trigger.
1 . A method for operating a wireless transceiver, the method comprising:
receiving a request to perform sounding on behalf of one or more beamformees;
determining a sounding control scheme on behalf of the one or more beamformees;
transmitting a sounding trigger to the one or more beamformees via a forward channel, the sounding trigger conveying aspects of the sounding control scheme, a training condition to be satisfied prior to the one or more beamformees is to respond to the sounding trigger, the training condition relating to at least one of a traffic type, location information, or a predicted dwell time; and
receiving at least one dedicated training signal from the one or more beamformees via a reverse channel in response to the condition of the sounding trigger being satisfied and according to the sounding control scheme, the at least one dedicated training signal including a partial bandwidth training signal.
2 . The method for operating the wireless transceiver of claim 1 , wherein for each of the received dedicated training signal:
estimating forward channel state information (CSI) derived based on the dedicated training signal from an associated beamformee; and wherein subsequent packets are precoded with precoding derived from the forward CSI for transmission to the associated beamformee via the forward channel.
3 . The method for operating the wireless transceiver of claim 2 , wherein estimating the forward CSI comprises:
measuring channel information from the dedicated training signal received via the reverse channel;
calculating a CSI for the reverse channel from the measured channel information; and
deriving the forward CSI for the forward channel from the CSI for the reverse channel in view of characteristics of a radio frequency front end of the transceiver, wherein the subsequent packets are transmitted to the associated beamformee via the forward channel.
4 . The method for operating the wireless transceiver of claim 1 , wherein the receiving at least one dedicated training signal from the one or more beamformees comprises:
receiving multiple dedicated training signals from the associated beamformee in response to the sounding trigger.
5 . The method for operating the wireless transceiver of claim 4 ,
wherein the sounding trigger indicates a sounding schedule for additional dedicated training signals from the associated beamformee based on the sounding control scheme, and
wherein the multiple dedicated training signals from the associated beamformee are received at timed intervals based on the sounding schedule.
6 . The method for operating the wireless transceiver of claim 1 , wherein receiving at least one dedicated training signal from the one or more beamformees comprises:
receiving multiple dedicated training signals from different beamformees in response to the sounding trigger.
7 . The method for operating the wireless transceiver of claim 6 ,
wherein the multiple dedicated training signals are received sequentially from the different beamformees, and
wherein each of the different beamformees determine a response time based on a packet length of the dedicated training signal in view of the sounding trigger.
8 . The method for operating the wireless transceiver of claim 6 ,
wherein the sounding trigger indicates a separate spatial stream for each of the different beamformees to send the dedicated training signal; and
wherein the multiple dedicated training signals are received simultaneously from the different beamformees on separate spatial streams.
9 . The method for operating the wireless transceiver of claim 1 ,
wherein the sounding trigger indicates a sounding schedule comprising at least one of: a sounding interval, a sounding position, and a schedule expiration.
10 . The method for operating the wireless transceiver of claim 9 , wherein the sounding schedule indicates sounding times for a group of beamformees to send dedicated training signals via the reverse channel.
11 . The method for operating the wireless transceiver of claim 1 ,
wherein the sounding trigger indicates training options for the beamformee to format the dedicated training signal including at least one of: repeated symbols, partial bandwidth, and a number of bits.
12 . The method for operating the wireless transceiver of claim 1 ,
wherein the sounding trigger indicates station information to enable different beamformees to send multiple dedicated training signals, wherein the station information comprising at least one of: a station list, a station identifier, and MAC address.
13 . The method for operating the wireless transceiver of claim 1 , further comprising:
transmitting additional sounding triggers to target additional beamformees, wherein
a separate additional dedicated training signal is received from each of the additional beamformees in response to each additional sounding trigger.
14 . The method for operating the wireless transceiver of claim 1 ,
wherein the sounding trigger is not preceded by an announcement frame, and the dedicated training signal is a null data packet.
15 . One or more non-transitory computer-readable media containing instructions which, when executed by one or more processors, cause a system to perform operations, the operations comprising:
receive a request to perform sounding on behalf of one or more beamformees;
determine a sounding control scheme on behalf of one or more beamformees;
transmit a sounding trigger to the one or more beamformees via a forward channel, the sounding trigger to convey an aspect of the sounding control scheme, wherein a training condition to be satisfied prior to the one or more beamformees is to respond to the sounding trigger, the training condition relating to at least one of a traffic type, location information, or a predicted dwell time; and
receive at least one dedicated training signal from the one or more beamformees via a reverse channel in response to the condition being satisfied, the at least one dedicated training signal including a partial bandwidth training signal.
16 . The one or more non-transitory computer-readable media of claim 15 , wherein the operations further comprise, for each of the received dedicated training signals:
estimate forward channel state information (CSI) derived based on the dedicated training signal from an associated beamformee; and wherein subsequent packets are precoded with precoding derived from the forward CSI for transmission to the associated beamformee via the forward channel.
17 . The one or more non-transitory computer-readable media of claim 16 , wherein estimating the forward CSI comprises:
measuring channel information from the dedicated training signal received via the reverse channel;
calculating a CSI for the reverse channel from the measured channel information; and
deriving the forward CSI for the forward channel from the CSI for the reverse channel in view of characteristics of a radio frequency front end of a transceiver, wherein the subsequent packets are transmitted to the associated beamformee via the forward channel.
18 . The one or more non-transitory computer-readable media of claim 15 , wherein the receiving at least one dedicated training signal from the one or more beamformees comprises:
receiving multiple dedicated training signals from the associated beamformee in response to the sounding trigger.
19 . The one or more non-transitory computer-readable media of claim 18 ,
wherein the sounding trigger indicates a sounding schedule for additional dedicated training signals from the associated beamformee, and
wherein the multiple dedicated training signals from the associated beamformee are received at timed intervals based on the sounding schedule.
20 . The one or more non-transitory computer-readable media of claim 15 , wherein receiving at least one dedicated training signal from the one or more beamformees comprises:
receiving multiple dedicated training signals from different beamformees in response to the sounding trigger.