Internal functional split in an O-RAN based massive MIMO radio unit and internal communication protocols

1. An active antenna comprising:

a main processor comprising an O-RAN front-haul interface and a post-O-RAN interface that is coupled to an output of the O-RAN front-haul interface, the post-O-RAN interface being configured to parse user-plane packets and control-plane packets received from the O-RAN front-haul interface to provide a plurality of output data streams in a frequency domain; and

a plurality of secondary processors that are configured to receive the output data streams, respectively, from the main processor and to transform data of the output data streams from the frequency domain into a time domain.

2. The active antenna of claim 1 , wherein the post-O-RAN interface of the main processor is further configured to apply a plurality of beamforming weights in the frequency domain.

3. The active antenna of claim 2 , wherein the post-O-RAN interface of the main processor is still further configured to compress beamforming-weighted data.

4. The active antenna of claim 1 , wherein the O-RAN front-haul interface of the main processor is configured to receive an input data stream via an Ethernet link and to output the user-plane packets and the control-plane packets to the post-O-RAN interface of the main processor based on the input data stream.

5. The active antenna of claim 4 , further comprising an optical connector that is coupled between the Ethernet link and a baseband unit.

6. The active antenna of claim 1 ,

wherein the data of the output data streams comprises user-plane data of a protocol for downlink communications from the main processor to the secondary processors,

wherein the output data streams further comprise control-plane information of the protocol, and

wherein the secondary processors are further configured to separate the user-plane data of the protocol from the control-plane information of the protocol.

7. The active antenna of claim 6 , wherein the secondary processors are still further configured to:

decompress the user-plane data of the protocol; and

apply antenna calibration parameters to the user-plane data of the protocol in the frequency domain.

8. The active antenna of claim 1 , wherein the post-O-RAN interface of the main processor is further configured to apply antenna calibration parameters in the frequency domain.

9. The active antenna of claim 1 ,

wherein the main processor comprises a main field-programmable gate array (FPGA), and

wherein the secondary processors comprise a plurality of secondary FPGAs, respectively, that are coupled to the main FPGA.

10. The active antenna of claim 1 , further comprising an array of radiating elements,

wherein the main processor and the secondary processors are on a back side of the array of radiating elements.

11. The active antenna of claim 1 , wherein the main processor further comprises a pre-O-RAN interface that is coupled to an input of the O-RAN front-haul interface, the pre-O-RAN interface being configured to generate user-plane packets using data received from the secondary processors through a protocol for uplink communications from the secondary processors to the main processor.

12. The active antenna of claim 1 , wherein the post-O-RAN interface of the main processor is further configured to continue sending the output data streams to the secondary processors when no data is available from the O-RAN front-haul interface of the main processor.

13. The active antenna of claim 12 , wherein the output data streams comprise dummy values when no data is available from the O-RAN front-haul interface of the main processor.

14. An active antenna comprising:

a main processor comprising an O-RAN front-haul interface and a post-O-RAN interface that is coupled to an output of the O-RAN front-haul interface; and

a plurality of secondary processors,

wherein the main processor is configured to output a plurality of data streams in a frequency domain to the secondary processors, respectively, each of the data streams comprising a header that includes control-plane information,

wherein each of the data streams comprises a guard section, and

wherein the header that includes the control-plane information is in the guard section.

15. The active antenna of claim 14 ,

wherein the data streams comprise respective downlink data streams, and

wherein the main processor is further configured to receive a plurality of uplink data streams from the secondary processors, respectively, each of the uplink data streams comprising user-plane data and a header.

16. The active antenna of claim 14 , wherein each of the data streams further comprises I/Q data for a plurality of radio frequency (RF) channels.

17. The active antenna of claim 16 ,

wherein the header that includes the control-plane information is in a first word of a first of the data streams, and

wherein a first frequency point of the first of the data streams comprises I/Q data in a second word of the first of the data streams.

18. The active antenna of claim 17 , wherein the first word of the header has a first number of bits that is equal to a second number of bits of the second word that has the I/Q data therein.

19. The active antenna of claim 14 , wherein the header that includes the control-plane information is part of a packet-based protocol that also includes I/Q data.