Radio over Ethernet

1. A method of wireless communication utilizing baseband circuitry in communication with radio circuitry via an Ethernet communication link, the method comprising:

recovering a first clock frequency at the baseband circuitry from a grandmaster clock provided from primary reference clock (PRC) circuitry;

synchronizing a frequency of a first internal reference clock of the baseband circuitry based on the recovered clock frequency;

recovering a second clock frequency at the radio circuitry from a signal received over the Ethernet communication link from the baseband circuitry, the second recovered clock frequency being frequency locked to the grandmaster clock;

synchronizing a frequency of a second internal reference clock of the radio circuitry based on the second clock frequency; and

synchronizing a phase of the first internal reference clock and a phase of the second internal reference clock, a phase offset between the phase of the first internal reference clock and the phase of the second internal reference clock being determined by utilizing a time stamped packet sent by the baseband circuitry to the radio circuitry via the Ethernet communication link and returned by the radio circuitry to the baseband circuitry via the Ethernet communication link.

2. The method according to claim 1 , wherein the first internal reference clock is synchronized to the grandmaster clock, and

wherein the second internal reference clock is synchronized to the first internal reference clock through a hierarchical master-slave architecture.

3. The method according to claim 2 , wherein the PRC circuitry is configured as a master and the baseband circuitry is configured as a slave with respect to the PRC circuitry in the hierarchical master-slave architecture; and wherein the baseband circuitry is configured as a master with respect to the radio circuitry that is configured as a slave in the hierarchical master-slave architecture.

4. The method according to claim 1 , wherein the synchronization of the first internal reference clock and the synchronization of the second internal reference clock utilize the Synchronous Ethernet (SyncE) standard.

5. The method according to claim 1 , wherein the synchronizing the phase comprises:

transmitting the time stamped packet from the baseband circuitry to the radio circuitry that has been time stamped with a first timestamp representing a time at which the packet is transmitted to the radio circuitry;

time stamping the time stamped packet upon receipt by the radio circuitry with a second timestamp representing a time at which the packet is received by the radio circuitry;

time stamping the time stamped packet with a third timestamp representing a time at which the packet is to be sent from the radio circuitry to the baseband circuitry;

transmitting the time stamped packet to the baseband circuitry;

time stamping the time stamped packet upon receipt by the baseband circuitry with a fourth timestamp representing a time at which the packet is received by the baseband circuitry; and

calculating the phase offset based on the timestamps.

6. The method according to claim 5 , wherein the synchronization of the phase comprises:

adjusting the phase of the second internal reference clock based on the phase offset.

7. The method according to claim 6 , wherein the synchronization of the phase further comprises:

measuring a delay through a nondeterministic component of at least one component from the baseband circuitry or the radio circuitry; and

calculating the phase offset based on the delay.

8. The method according to claim 7 , wherein the measuring of the delay through the nondeterministic component comprises:

first detecting a predetermined code in a data stream before processing by the nondeterministic component,

second detecting the predetermined code in the data stream after processing by the nondeterministic component, and

measuring a time difference between the first detection and the second detection.

9. The method according to claim 8 , wherein the first internal reference clock is synchronized to the grandmaster clock, and

wherein the second internal reference clock is synchronized to the first internal reference clock through a hierarchical master-slave architecture.

10. The method according to claim 8 , wherein the synchronization of the phase further comprises:

translating the second internal reference clock from a current time base to another time base.

11. The method according to claim 10 , wherein the translating comprises:

determining a timing offset between the current time base and the other time base; and

adjusting the other time base based on the determined timing offset.

12. The method according to claim 1 , wherein the synchronizing the phase comprises:

determining a roundtrip transit time over the Ethernet communication link utilizing the time stamped packets exchanged between the baseband circuitry and the radio circuitry via the Ethernet communication link; and

determining the phase offset based on the roundtrip transit time.

13. A wireless communication device, comprising:

a baseband module configured to perform signal processing on a data stream;

a radio module configured to wirelessly transmit the data stream; and

an Ethernet communication link communicatively coupling the baseband module to the radio module, wherein a first clock frequency and a first clock phase of the baseband module and a second clock frequency and a second clock phase of the radio module are synchronized via the Ethernet communication link, wherein the synchronization of the second clock phase of the radio module with the first clock phase of the baseband module includes determining a phase offset between the first clock phase and the second clock phase utilizing a time stamped packet sent by the baseband module to the radio module via the Ethernet communication link and returned by the radio module to the baseband module via the Ethernet communication link.

14. The wireless communication device of claim 13 , wherein the first clock frequency of the baseband module and the second clock frequency of the radio module are synchronized utilizing a hierarchical master-slave architecture.

15. The wireless communication device of claim 14 , wherein the baseband module further comprises:

a delay measurement module configured to measure a delay through a nondeterministic component of at least one component from the baseband module.

16. The wireless communication device of claim 15 , wherein the delay measurement module is configured to:

first detect a predetermined code in a data stream before processing by the nondeterministic component,

second detect the predetermined code in the data stream after processing by the nondeterministic component, and

measure a time difference between the first detection and the second detection to measure the delay.

17. The wireless communication device of claim 13 , wherein the baseband module further comprises:

a clock and data recovery (CDR) unit configured to receive a grandmaster clock and to recover the first clock frequency and the first clock phase of the baseband module from the received grandmaster clock; and

a clock generation unit configured to generate a baseband reference clock based on the recovered first clock frequency and the recovered first clock phase of the baseband module.

18. The wireless communication device of claim 13 , wherein the radio module further comprises:

a clock and data recovery (CDR) unit configured to receive a signal from the baseband module and to recover the second clock frequency and the second clock phase of the radio module from the received signal; and

a clock generation unit configured to generate a radio reference clock based on the recovered second clock frequency and the recovered second clock phase of the radio module.

19. The wireless communications device of claim 13 , wherein the synchronization of the second clock phase of the radio module with the first clock phase of the baseband module further includes:

determining a roundtrip transit time over the Ethernet communication link utilizing the time stamped packets exchanged between the baseband module and the radio module via the Ethernet communication link, and

determining the phase offset based on the roundtrip transit time.

20. A method of wireless communication utilizing baseband circuitry in communication with radio circuitry via an Ethernet communication link, the method comprising:

recovering a first clock frequency at the baseband circuitry from a grandmaster clock, wherein the baseband circuitry receives the grandmaster clock utilizing a hierarchical master-slave architecture;

synchronizing a first internal reference clock of the baseband circuitry based on the recovered first clock frequency;

recovering a second clock frequency at the radio circuitry from a signal received from the baseband circuitry, the recovering of the second clock frequency utilizing the hierarchical master-slave architecture, wherein the recovered second clock frequency is frequency locked to the grandmaster clock; and

synchronizing a second internal reference clock of the radio circuitry based on the second clock frequency recovered at the radio circuitry;

wherein synchronizing a first clock phase of the first internal reference clock of the baseband circuitry and a second clock phase of the second internal reference clock of the radio circuitry, wherein the synchronizing the first clock phase comprises:

determining a phase offset utilizing time stamped packets exchanged between the baseband module and the radio module via the Ethernet communication link, and

measuring a delay through a nondeterministic component of at least one component of the baseband circuitry or the radio circuitry.