Coordinated beamforming with active synchronization

1. A first multiple input multiple output (MIMO) transceiver configured to communicate with a first wireless station in a first wireless network according to a first symbol alignment, the first MIMO transceiver comprising:

a signal detection circuit coupled to a plurality of receive chains, the signal detection circuit configured to:

detect a signal in a second wireless network from a second MIMO transceiver to a second wireless station in the second wireless network via the receive chains, wherein a coverage area of the second wireless network at least partially overlaps a coverage area of the first wireless network; and

determine a second symbol alignment of the signal in the second wireless network based on a preamble of the signal in the second wireless network; and

a precoding determination circuit coupled to a plurality of transmit chains, the precoding determination circuit configured to:

determine a precoding matrix that is configured to create a null in a location where the second wireless station is physically positioned; and

determine the first symbol alignment, wherein the first symbol alignment is synchronized with the second symbol alignment, and wherein the transmit chains are configured to:

pre-code a signal in the first wireless network using the precoding matrix; and

align symbols of the signal in the first wireless network according to the first symbol alignment.

2. The first MIMO transceiver of claim 1 , wherein the signal in the second wireless network is a first signal in the second wireless network and the signal in the first wireless network is a first signal in the first wireless network, and wherein:

the signal detection circuit is further configured to:

detect a second signal in the second wireless network from the second MIMO transceiver to the second wireless station via the receive chains; and

determine a third symbol alignment of the second signal in the second wireless network based on a preamble of the second signal in the second wireless network; and

the precoding determination circuit is further configured to:

select the precoding matrix that is configured to create the null in the location where the second wireless station is physically positioned; and

determine a fourth symbol alignment that is synchronized with the third symbol alignment, wherein the transmit chains are configured to:

pre-code a second signal in the first wireless network using the precoding matrix; and

align symbols of the second signal in the first wireless network according to the fourth symbol alignment.

3. The first MIMO transceiver of claim 1 , wherein the precoding matrix is a first precoding matrix and the signal in the first wireless network is a first signal in the first wireless network, and wherein:

the signal detection circuit is further configured to:

detect a signal in a third wireless network from a third MIMO transceiver to a third wireless station in the third wireless network via the receive chains, wherein a coverage area of the third wireless network at least partially overlaps the coverage area of the first wireless network; and

determine a third symbol alignment of the signal in the third wireless network based on a preamble of the signal in the third wireless network; and

the precoding determination circuit is further configured to:

determine a second precoding matrix that is configured to create a null in a location where the third wireless station is physically positioned; and

determine a fourth symbol alignment that is synchronized with the third symbol alignment, wherein the transmit chains are configured to:

pre-code a second signal in the first wireless network using the second precoding matrix; and

align symbols of the second signal in the first wireless network according to the fourth symbol alignment.

4. The first MIMO transceiver of claim 1 , wherein the signal detection circuit is further configured to determine the second wireless station is intended to receive the signal in the second wireless network from the second MIMO transceiver based on the preamble of the signal in the second wireless network.

5. The first MIMO transceiver of claim 1 , wherein the signal detection circuit is further configured to detect the signal in the second wireless network during a back-off period of time that the first MIMO transceiver is to delay all transmissions.

6. The first MIMO transceiver of claim 1 , wherein the second wireless network is configured as a wireless local area network (WLAN) configured as a hub and spoke network around the second MIMO transceiver and the first wireless network is configured as a WLAN configured as a hub and spoke network around the first MIMO transceiver.

7. The first MIMO transceiver of claim 1 , further comprising a plurality of antennas configured to wirelessly transmit the signal in the first wireless network, wherein the signal in the first wireless network is wirelessly transmitted by the antennas during a period of time that the signal in the second wireless network is still being detected.

8. The first MIMO transceiver of claim 7 , wherein the signal in the first wireless network is wirelessly transmitted such that the preamble of the signal in the second wireless network and a preamble of the signal in the first wireless network are aligned in a time domain.

9. The first MIMO transceiver of claim 7 , wherein the antennas are configured to wirelessly transmit the signal in the first wireless network such that the null is created by destructive interference occurring between the signal in the first wireless network being wirelessly transmitted by two or more of the antennas.

10. The first MIMO transceiver of claim 7 , wherein the signal in the first wireless network is wirelessly transmitted such that bursts of energy that occur in the null in a time domain are positioned between symbols of the signal from the second MIMO transceiver.

11. A method comprising:

transmitting a first signal to a wireless station of a wireless network using a precoding matrix and a symbol alignment to avoid interference to concurrent transmissions of one or more overlapping wireless networks at a location of one or more selected wireless stations of the overlapping wireless networks:

wherein the precoding matrix is configured to create a null in the location of the selected wireless stations within overlapping coverage areas of the overlapping wireless networks and the wireless network, and

wherein the symbol alignment for second signals to the wireless station of the wireless network is configured based on a preamble of a detected signal to another wireless station of the overlapping wireless networks.

12. The method of claim 11 , wherein during concurrent transmission by multiple transceivers of the overlapping wireless networks and the wireless network, the wireless station of the wireless network receives the first signal that is pre-coded according to the precoding matrix to avoid interference with the concurrent transmissions of the overlapping wireless networks and the first signal that is pre-coded according to the precoding matrix includes the symbol alignment to improve reception.

13. The method of claim 11 further comprising:

determining the symbol alignment for the second signals to the wireless station of the wireless network based on a symbol alignment of the detected signal to another wireless station of the overlapping wireless networks:

wherein the symbol alignment for the second signals to the wireless station of the wireless network is configured such that bursts of energy that occur in the null in the location of the selected wireless stations of the overlapping wireless networks in a time domain are positioned between symbols of third signals to the selected wireless stations.

14. A method of operating a first multiple input multiple output (MIMO) transceiver to communicate with a first wireless station in a first wireless network according to a first symbol alignment, the method comprising:

detecting a signal in a second wireless network from a second MIMO transceiver to a second wireless station in the second wireless network, wherein a coverage area of the second wireless network at least partially overlaps a coverage area of the first wireless network;

determining a second symbol alignment of the signal in the second wireless network based on a preamble of the signal in the second wireless network;

determining a precoding matrix that is configured to create a null in a location where the second wireless station is physically positioned;

determining the first symbol alignment, wherein the first symbol alignment is synchronized with the second symbol alignment;

precoding a signal in the first wireless network using the precoding matrix; and

aligning symbols of the signal in the first wireless network according to the first symbol alignment.

15. The method of claim 14 , wherein the signal in the second wireless network is a first signal in the second wireless network and the signal in the first wireless network is a first signal in the first wireless network, the method further comprising:

detecting a second signal in the second wireless network from the second MIMO transceiver to the second wireless station;

determining a third symbol alignment of the second signal in the second wireless network based on a preamble of the second signal in the second wireless network;

selecting the precoding matrix that is configured to create the null in the location where the second wireless station is physically positioned;

determining a fourth symbol alignment that is synchronized with the third symbol alignment;

precoding a second signal in the first wireless network using the precoding matrix; and

aligning symbols of the second signal in the first wireless network according to the fourth symbol alignment.

16. The method of claim 14 , wherein the precoding matrix is a first precoding matrix and the signal in the first wireless network is a first signal in the first wireless network, the method further comprising:

detecting a signal in a third wireless network from a third MIMO transceiver to a third wireless station in the third wireless network, wherein a coverage area of the third wireless network at least partially overlaps the coverage area of the first wireless network;

determining a third symbol alignment of the signal in the third wireless network based on a preamble of the signal in the third wireless network;

determining a second precoding matrix that is configured to create a null in a location where the third wireless station is physically positioned;

determining a fourth symbol alignment that is synchronized with the third symbol alignment;

precoding a second signal in the first wireless network using the second precoding matrix; and

aligning symbols of the second signal in the first wireless network according to the fourth symbol alignment.

17. The method of claim 14 further comprising determining the second wireless station is intended to receive the signal in the second wireless network from the second MIMO transceiver based on the preamble of the signal in the second wireless network.

18. The method of claim 14 , wherein the detecting the signal in the second wireless network occurs during a back-off period of time that transmission of the signal in the first wireless network is to be delayed.

19. The method of claim 14 , wherein the signal in the first wireless network is wirelessly transmitted such that the preamble of the signal in the second wireless network and a preamble of the signal in the first wireless network are aligned in a time domain.

20. The method of claim 14 , wherein the signal in the first wireless network is wirelessly transmitted such that bursts of energy that occur in the null in a time domain are positioned between symbols of the signal from the second MIMO transceiver.