Frame formats for distributed MIMO
Disclosed herein are related to systems and methods for a multiple-input multiple-output (MIMO) communication. In one aspect, during a first time period, a master access point transmits, to a slave access point, information for a joint transmission by the master access point and the slave access point. In one aspect, the slave access point estimates synchronizing information for the joint transmission, according to the information for the joint transmission. In one aspect, during a second time period after the first time period, the master access point transmits a portion of a steered frame to a station device. In one aspect, the slave access point transmits, during the second time period, the portion of the steered frame to the station device, based on the synchronizing information. In one aspect, the station device decodes the portion of the steered frame to obtain content data in the portion of the steered frame.
1. A first access point for a multiple-input multiple-output (MIMO) communication comprising:
a transceiver; and
a steering controller, the steering controller configured to:
cause the transceiver to transmit, during a first time period, to a second access point, information for a joint transmission by the first access point and the second access point, the information for the joint transmission allowing the second access point to estimate synchronization information for the joint transmission, and
cause the transceiver to transmit, during a second time period after the first time period, a portion of a steered frame to a station device, while the second access point transmits the portion of the steered frame to the station device according to the synchronization information, the joint transmission of the portion of the steered frame by the first access point and the second access point allowing the station device to receive the portion of the steered frame and decode the portion of the steered frame to obtain content data in the portion of the steered frame,
wherein the steered frame transmitted by the first access point includes a mid-amble, wherein the second access point is configured to bypass a transmission, while the first access point transmits the mid-amble of the steered frame, the mid-amble allowing the second access point to resynchronize for another joint transmission of another portion of the steered frame by the first access point and the second access point, the mid-amble allowing the second access point to transition, during the transmission of the mid-amble by the first access point, from a transmit mode to a receive mode and transition back to the transmit mode for the another joint transmission of the another portion of the steered frame by the first access point and the second access point.
2. The first access point of claim 1 , wherein the second time period is immediately after the first time period.
3. The first access point of claim 1 , wherein the steering controller is configured to cause the transceiver to transmit, during the second time period, a training field to the station device, while the second access point transmits the training field to the station device during the second time period, the training field transmitted by the first access point and the second access point allowing the station device to adjust a gain setting to receive the portion of the steered frame.
4. A first access point for a multiple-input multiple-output (MIMO) communication comprising:
a transceiver; and
a steering controller, the steering controller configured to:
cause the transceiver to transmit, during a first time period, to a second access point, information for a joint transmission by the first access point and the second access point, the information for the joint transmission allowing the second access point to estimate synchronization information for the joint transmission,
cause the transceiver to transmit, during a second time period after the first time period, a portion of a steered frame to a station device, while the second access point transmits the portion of the steered frame to the station device according to the synchronization information, the joint transmission of the portion of the steered frame by the first access point and the second access point allowing the station device to receive the portion of the steered frame and decode the portion of the steered frame to obtain content data in the portion of the steered frame,
cause the transceiver to transmit, during a third time period after the first time period and the second time period, a null data packet to the second access point, the null data packet allowing the second access point to resynchronize for another joint transmission of another steered frame by the first access point and the second access point, and
cause the transceiver to transmit, during a fourth time period after the third time period, the another steered frame to the station device, while the second access point transmits the another steered frame to the station device during the fourth time period after the resynchronizing, the another steered frame transmitted by the first access point and the second access point allowing the station device to receive the another steered frame and decode the another steered frame to obtain additional content data in the another steered frame.
5. The first access point of claim 4 , wherein the steering controller is configured to:
cause the transceiver to receive, during a fifth time period between the second time period and the third time period, from the station device an acknowledgement frame, and schedule the another joint transmission of the another steered frame, in response to the acknowledgement frame.
6. The first access point of claim 1 , wherein the steering controller is configured to cause the transceiver to:
transmit a unique pilot sequence associated with the first access point to enable the station device to estimate additional synchronization information, and
receive the additional synchronization information as a feedback.
7. An access point for a multiple-input multiple-output (MIMO) communication comprising:
a transceiver; and
a steering controller, the steering controller configured to:
cause the transceiver to receive, during a first time period, from another access point, information for a joint transmission by the access point and the another access point,
estimate synchronization information for the joint transmission by estimating a carrier frequency offset, a sampling frequency offset, a first reference value for a common phase offset, or a second reference value for a timing offset with respect to the another access point, according to the information for the joint transmission, and
cause the transceiver to transmit, during a second time period after the first time period, a portion of a steered frame to a station device according to the synchronization information, while the another access point transmits the portion of the steered frame to the station device during the second time period, the portion of the steered frame transmitted by the access point and the another access point allowing the station device to receive the portion of the steered frame and decode the portion of the steered frame to obtain content data in the portion of the steered frame.
8. The access point of claim 7 , wherein the second time period is immediately after the first time period.
9. The access point of claim 7 , wherein the steering controller is configured to determine the synchronization information according to a change in a phase offset or a timing offset between a sounding sequence and a steering sequence.
10. The access point of claim 7 ,
wherein the steered frame transmitted by the another access point includes a mid-amble,
wherein the steering controller is configured to cause the transceiver to bypass a transmission, while the another access point transmits the mid-amble of the steered frame,
wherein the steering controller is configured to, during the transmission of the mid-amble by the another access point:
resynchronize for another joint transmission of another portion of the steered frame by the access point and the another access point, and
transition, from a transmit mode to a receive mode and transition back to the transmit mode for the another joint transmission of the another portion of the steered frame by the access point and the another access point.
11. The access point of claim 7 , wherein the steering controller is configured to cause the transceiver to transmit, during the second time period, a training field to the station device, while the another access point transmits the training field to the station device during the second time period, the training field transmitted by the access point and the another access point allowing the station device to adjust a gain setting to receive the portion of the steered frame.
12. The access point of claim 7 , wherein the steering controller is configured to:
cause the transceiver to receive, during a third time period after the first time period and the second time period, a null data packet from the another access point, the null data packet allowing the access point to resynchronize for another joint transmission of another steered frame by the access point and the another access point, and
cause the transceiver to transmit, during a fourth time period after the third time period, the another steered frame to the station device after the resynchronizing, while the another access point transmits the another steered frame to the station device during the fourth time period, the another steered frame transmitted by the access point and the another access point allowing the station device to receive the another steered frame and decode the another steered frame to obtain additional content data in the another steered frame.
13. The access point of claim 12 , wherein the steering controller is configured to:
cause the transceiver to receive, during a fifth time period between the second time period and the third time period, from the station device an acknowledgement frame.
14. The access point of claim 7 , wherein the steering controller is configured to cause the transceiver to:
transmit a unique pilot sequence associated with the access point to enable the station device to estimate additional synchronization information, and
receive the additional synchronization information as a feedback.
15. A first access point for a multiple-input multiple-output (MIMO) communication comprising:
a first transceiver;
a second transceiver; and
a steering controller, the steering controller configured to:
cause the first transceiver to communicate with a second access point through a first channel frequency, synchronization information for a joint transmission by the first access point and the second access point, and
cause the second transceiver to transmit to a station device through a second channel frequency, a portion of a steered frame, while the second access point transmits, through the second channel frequency, the portion of the steered frame to the station device according to the synchronization information for the joint transmission.
16. The first access point of claim 15 , wherein the synchronization information includes a carrier frequency offset or a sampling frequency offset.
17. The first access point of claim 15 , wherein the second access point is configured to synchronize with the first access point for the joint transmission according to the synchronization information.
18. The first access point of claim 15 , wherein the first transceiver and the second transceiver share a same reference clock.
19. The first access point of claim 4 , wherein the steering controller is configured to estimate the synchronization information for the joint transmission by estimating a carrier frequency offset, a sampling frequency offset, a first reference value for a common phase offset, or a second reference value for a timing offset with respect to the second access point.
20. The first access point of claim 4 , wherein the steering controller is configured to determine the synchronization information according to a change in a phase offset or a timing offset between a sounding sequence and a steering sequence.