Synchronization of large antenna count systems
View Patent ↗Techniques are disclosed relating to synchronization of radios in a large antenna count (LAC) system. In some embodiments, a LAC system includes a plurality of slave radios, a clock and trigger distribution system, and a master device. In these embodiments, the plurality of slave radios are configured to establish a fixed relationship between a reference clock and their respective local clocks. In these embodiments, the master device and plurality of slave radios are configured to generate and align respective common periodic time reference (CPTR) signals, at a lower frequency than the local clocks. In these embodiments, the master device is configured to transmit a trigger signal based on its CPTR and the plurality of slave radios are configured to perform an action based on the trigger at a subsequent edge of their CPTRs. This may allow synchronization of sampling for antennas in a massive MIMO base station, for example. In some embodiments the master device a radio and includes a local clock, is configured to establish and maintain a fixed relationship between a reference clock and its local clock, and is configured to perform an action based on the trigger at the subsequent edge of its CPTR.
1. A large antenna count (LAC) system, comprising:
a master device;
a plurality of slave radios communicatively coupled to the master device and to respective antennas in the large antenna count system, wherein each slave radio includes a local clock;
a clock and trigger distribution system, coupled to the master device and the plurality of slave radios, wherein the clock and trigger distribution system comprises a hierarchy of clock and trigger distribution modules;
wherein the plurality of slave radios are configured to establish and maintain a fixed relationship between a reference clock and their respective local clocks, wherein the reference clock is distributed via the clock and trigger distribution system;
wherein the master device and the plurality of slave radios are configured to generate and align respective common periodic time reference signals that have a lower frequency than the respective local clocks;
wherein the master device is configured to transmit, based on an edge of its common periodic time reference signal, a trigger signal via the clock and trigger distribution system to the plurality of slave radios; and
wherein the plurality of slave radios are configured to perform an action based on the trigger signal at a subsequent edge of their common periodic time reference signals.
2. The large antenna count (LAC) system of claim 1 , wherein the master device is configured to receive a trigger indication and wait until the edge of its common periodic time reference signal to transmit the trigger signal.
3. The large antenna count (LAC) system of claim 1 , wherein the action is a sampling action.
4. The large antenna count (LAC) system of claim 1 , wherein the fixed relationship includes a phase lock.
5. The large antenna count (LAC) system of claim 1 , wherein the reference clock has a lower frequency than the local clocks.
6. The large antenna count (LAC) system of claim 1 , wherein, to align the common periodic time reference signals, the slave radios are each configured to measure and report a relationship between the reference signal and a respective common periodic time reference signal.
7. The large antenna count (LAC) system of claim 6 , wherein the slave radios are each configured to use a clock at double the rate of a respective local clock and double data rate circuitry to measure and report the relationship.
8. The large antenna count (LAC) system of claim 1 , wherein a period of the common periodic time reference signals is configured to be greater than a propagation delay of the clock and trigger distribution system.
9. A method, comprising:
establishing, by a plurality of slave radios, a fixed relationship between a reference clock and respective local clocks, wherein the reference clock is distributed to the slave radios via a clock and trigger distribution system;
a master device and the plurality of slave radios generating and aligning respective common periodic time reference signals that have a lower frequency than the respective local clocks;
the master device transmitting, based on an edge of its common periodic time reference signal, a trigger signal via the clock and trigger distribution system to the plurality of slave radios; and
the plurality of slave radios performing an action based on the trigger at a subsequent edge of their common periodic time reference signals.
10. The method of claim 9 , further comprising:
the master device receiving a trigger indication prior to the edge of its common periodic time reference signal and transmitting the trigger signal in response to the edge.
11. The method of claim 9 , wherein the action is a sampling action for uplink wireless data.
12. The method of claim 9 , wherein the fixed relationship includes a phase lock and discipline to a particular frequency.
13. The method of claim 9 , further comprising:
the slave radios each measuring and reporting a relationship between the reference signal and a respective common periodic time reference signal.
14. The method of claim 9 , wherein the measuring is performed using a clock at double a rate of the respective local clock.
15. The method of claim 9 , further comprising:
configuring a period of the common periodic time reference signals to be greater than a propagation delay of the clock and trigger distribution system.
16. A non-transitory computer-readable medium having instructions stored thereon that are capable of causing or configuring a computing system to perform operations comprising:
establishing, by a plurality of slave radios, a fixed relationship between a reference clock and respective local clocks, wherein the reference clock is distributed to the slave radios via a clock and trigger distribution system;
a master device and the plurality of slave radios generating and aligning respective common periodic time reference signals that have a lower frequency than the respective local clocks;
the master device transmitting, based on an edge of its common periodic time reference signal, a trigger signal via the clock and trigger distribution system to the plurality of slave radios; and
the plurality of slave radios performing an action based on the trigger at a subsequent edge of their common periodic time reference signals.
17. The non-transitory computer-readable medium of claim 16 , wherein the operations further comprise:
the master device receiving a trigger indication prior to the edge of its common periodic time reference signal and transmitting the trigger signal in response to the edge.
18. The non-transitory computer-readable medium of claim 16 , wherein the action is a sampling action for received wireless signals.
19. The non-transitory computer-readable medium of claim 16 , wherein the operations further comprise:
configuring a period of the common periodic time reference signals to be greater than a propagation delay of the clock and trigger distribution system.
20. The non-transitory computer-readable medium of claim 16 , wherein the operations further comprise:
setting one or more event timers on the slave radios based on the trigger signal.