Communication device and method for reducing interference

1. A device configured to communicate a data in an orthogonal frequency division multiplexing (OFDM) system, comprising:

a radio frequency (RF) antenna configured to receive at least one reference signal from a second device via a plurality of channel paths;

a baseband modem configured to:

perform a channel estimation on the plurality of channel paths, wherein the channel estimation comprises determining a channel path gain, a channel path delay, and at least one of a channel path angle of arrival (AoA) or a channel path angle of departure (AoD); and

determine an analog beamforming to be produced by the device according to the channel estimation, wherein the analog beamforming is determined by determining an extremum value of the OFDM system, wherein the extremum value comprises a maximum for a signal-to-interference-plus-noise ratio (SINR) per sub-carrier or a minimum for an inter-symbol interference caused by channel delays; and

wherein the device is further configured to communicate the data with the second device using the analog beamforming.

2. The device of claim 1 , wherein the RF antenna and the baseband modem are integrated into a single unit.

3. The device of claim 1 , the baseband modem further configured to use a least square algorithm to determine the channel path gain.

4. The device of claim 1 , the baseband modem further configured to use multiple signal classification to determine the channel path AoA or the channel path AoD.

5. The device of claim 1 , the baseband modem further configured to use estimation of signal parameters via rotation invariance techniques to determine the channel path AoA or the channel path AoD.

6. The device of claim 1 , the baseband modem further configured to implement the channel estimation by using an uplink channel estimation to acquire a downlink channel information.

7. The device of claim 1 , the baseband modem being further configured to determine the analog beamforming direction by the following equation:

u

=

the

⁢

⁢

m

⁢

⁢

argmax

u

⁢

P

⁢

∑

m

=

1

l

⁢

G

m

⁢

sin

2

⁡

(

N

⁡

(

θ

m

-

u

)

2

)

sin

2

⁡

(

θ

m

-

u

2

)

1

+

P

⁢

∑

j

=

l

+

1

M

⁢

G

j

⁢

sin

2

⁡

(

N

⁡

(

θ

j

-

u

)

2

)

sin

2

⁡

(

θ

j

-

u

2

)

where u is the analog beamforming direction; P is a transmit power per each sub-carrier; G m and G j is a channel gain for the mth and a jth path, respectively; N is a number of antenna elements; θ m and θ j is an AoA or the AoD for the mth and jth paths, respectively; and M is a number of channel paths.

8. The device of claim 1 , the baseband modem being further configured to determine the analog beamforming direction by the following equation:

u

=

argmin

u

⁢

P

⁢

∑

j

=

l

+

1

M

⁢

G

j

⁢

sin

2

⁡

(

N

⁡

(

θ

j

-

u

)

2

)

sin

2

⁡

(

θ

j

-

u

2

)

where u is the analog beamforming direction; P is a transmit power per each sub-carrier; G j is a channel gain for a jth path; N is a number of antenna elements; and θ j is an AoA or AoD for the jth path.

9. A device configured to communicate a data in an orthogonal frequency division multiplexing (OFDM) system, comprising:

a radio frequency (RF) antenna configured to receive at least one reference signal from a second device via a plurality of channel paths;

a baseband modem configured to:

perform a channel estimation on the plurality of channel paths, wherein the channel estimation comprises determining a channel path delay for each of the plurality of channel paths; and

determine an analog beamforming to be produced by the device by determining a minimum for an inter-symbol interference caused by channel delays, wherein the analog beamforming is directed towards channel paths with a channel path delay with a duration equal to or less than a cyclic prefix duration of the OFDM system;

wherein the device is further configured to communicate the data with the second device using the analog beamforming.

10. The device of claim 9 , wherein the RF antenna and the baseband modem are integrated into a single unit.

11. The device of claim 9 , the baseband modem further configured to implement the channel estimation by using an uplink channel estimation to acquire a downlink channel information.

12. The device of claim 9 , the baseband modem being further configured to determine the analog beamforming by determining an extremum value for a metric beneficial to the OFDM system, wherein the extremum value for the metric comprises a maximum for a signal-to-interference-plus-noise ratio (SINR) per sub-carrier.

13. A method for a device to communicate a data in an orthogonal frequency division multiplexing (OFDM) system, comprising:

receiving at the device at least one reference signal from a second device via a plurality of channel paths;

performing a channel estimation on the plurality of channel paths, wherein the channel estimation comprises determining a channel path gain, a channel path delay, and at least one of a channel path angle of arrival (AoA) or a channel path angle of departure (AoD), wherein the analog beamforming is determined by determining an extremum value of the OFDM system, wherein the extremum value comprises a maximum for a signal-to-interference-plus-noise ratio (SINR) per sub-carrier or a minimum for an inter-symbol interference caused by channel delays;

determining an analog beamforming to be produced by the device according to the channel estimation; and

communicating the data using the analog beamforming.

14. The method of claim 13 , further comprising implementing the channel estimation by using an uplink channel estimation to acquire a downlink channel information.

15. The method of claim 13 , further comprising wherein determining the analog beamforming comprises determining an extremum value for a metric beneficial to the OFDM system, wherein determining the extremum value for the metric comprises determining a maximum for a signal-to-interference-plus-noise ratio (SINR) per sub-carrier.

16. The method of claim 13 , further comprising wherein determining the analog beamforming comprises determining an extremum value for a metric beneficial to the OFDM system, wherein determining the extremum value for the metric comprises determining a minimum for an inter-symbol interference caused by channel delays.

17. A method for a device to communicate a data in an orthogonal frequency division multiplexing (OFDM) system, comprising:

receiving at the device at least one reference signal from a second device via a plurality of channel paths;

performing a channel estimation on the plurality of channel paths, wherein the channel estimation comprises determining a channel path delay for each of the plurality of channel paths;

determining an analog beamforming to be produced by the device by determining a minimum for an inter-symbol interference caused by channel delays, wherein the analog beamforming is directed towards channel paths with a channel path delay with a duration equal to or less than a cyclic prefix duration of the OFDM system; and

communicating the data using the analog beamforming.

18. The method of claim 17 , further comprising wherein the channel estimation further comprises determining a channel path gain.

19. The method of claim 17 , further comprising wherein the channel estimation further comprises determining at least one of a channel path angle of arrival (AoA) or a channel path angle of departure (AoD).

20. The method of claim 17 , further comprising wherein determining the analog beamforming comprises determining an extremum value for a metric beneficial to the OFDM system, wherein determining the extremum value for the metric comprises determining a maximum for a signal-to-interference-plus-noise ratio (SINR) per sub-carrier.