Power-efficient communication synchronization
A communications system may include user equipment (UE) devices, non-geostationary orbit satellites, and gateways. The satellites may provide communications services to the UE devices. A given satellite may have a set of signal beams. The satellite may transmit bursts of repeated system synchronization blocks (SSBs), repeated first system information blocks, and repeated second system information blocks over each of its beams with different respective SSB periods separated in time by SSB offsets. The SSB periods may be relatively long to minimize power consumption on the satellite. Repeating the blocks may ensure that UE devices receive the blocks even if intervening objects are present between the UE devices and the satellite. The UE devices may use the blocks to synchronize with the network for registering with the network and for performing subsequent communications operations such as mobile-terminated (MT) services, mobile-originated (MO) services, and handover.
1 . A method of operating a communications satellite to perform wireless communications with user equipment (UE) devices, the method comprising:
periodically transmitting, with a first transmission period, a first burst of repetitions of a system synchronization block (SSB), the first burst being transmitted in a first signal beam;
subsequent to transmission of the first burst of repetitions of the SSB, periodically transmitting, in the first signal beam and with the first transmission period, a first burst of repetitions of a first system information block (SIB); and
periodically transmitting, with a second transmission period, a second burst of repetitions of the SSB, the second burst being transmitted in a second signal beam oriented at a different angle than the first signal beam.
2 . The method of claim 1 , wherein the second transmission period is offset in time from the first transmission period.
3 . The method of claim 2 , wherein the second transmission period and the first transmission period have equal durations.
4 . The method of claim 2 , wherein the first transmission period has a first duration, the second transmission period has a second duration that is less than the first duration, and there are more UE devices overlapping the second signal beam than the first signal beam.
5 . The method of claim 1 , wherein the first transmission period and the second transmission period have durations greater than 1 second.
6 . The method of claim 1 , further comprising:
subsequent to transmission of the second burst of repetitions of the SSB, periodically transmitting, in the second signal beam and with the second transmission period, a second burst of repetitions of the first SIB.
7 . The method of claim 6 , further comprising:
subsequent to transmission of the first burst of repetitions of the first SIB, periodically transmitting, in the first signal beam and with the first transmission period, a burst of repetitions of a second SIB that is different from the first SIB; and
subsequent to transmission of the second burst of repetitions of the SIB, periodically transmitting, in the second signal beam and with the second transmission period, a burst of repetitions of a third SIB that is different from the first SIB and the second SIB.
8 . The method of claim 7 , wherein the first transmission period comprises a first silent period after transmission of the burst of repetitions of the second SIB and the second transmission period comprises a second silent period after transmission of the burst of repetitions of the third SIB.
9 . The method of claim 7 , wherein the second SIB and the third SIB comprise ephemeris data associated with the communications satellite.
10 . The method of claim 7 , wherein the second SIB comprises information identifying the first signal beam and the second SIB comprises information identifying the second signal beam.
11 . The method of claim 10 , wherein the second SIB comprises information identifying a third signal beam of the communications satellite adjacent to the first signal beam, wherein the second SIB comprises information identifying a paging cycle of the third signal beam.
12 . The method of claim 1 , further comprising:
when the first signal beam overlaps a UE device in a connected mode, periodically transmitting the SSB with a third transmission period less than the second transmission period.
13 . The method of claim 1 , further comprising:
transmitting a system information block (SIB) that identifies a paging cycle for a given signal beam;
transmitting, during a user equipment (UE) device wake-up period associated with the paging cycle, a paging signal in the given signal beam; and
transmitting, in the given signal beam, the SSB appended to the paging signal.
14 . The method of claim 13 , further comprising:
receiving, from a gateway, a paging message, wherein the paging signal comprises repetitions of the paging message.
15 . The method of claim 13 , wherein transmitting the SSB appended to the paging signal comprises transmitting the SSB appended to the paging signal when a duration between the UE device wake-up period and a previous transmission of the SSB in the given signal beam exceeds a threshold duration, the method further comprising:
when the duration is less than the threshold duration, transmitting the paging signal without the SSB appended to the paging signal.
16 . The method of claim 1 , further comprising:
receiving, from a user equipment (UE) device overlapping a given signal beam, a message requesting mobile-originated (MO) communication services;
transmitting, in the given signal beam, a response to the message; and
transmitting, in the given signal beam, a system synchronization block (SSB) appended to the response.
17 . A method of operating a communications system, the method comprising:
periodically transmitting, via a first signal beam of a communications satellite, a first burst of repetitions of a system synchronization block (SSB) using a first transmission period; and
periodically transmitting, via a second signal beam of the communications satellite, a second burst of repetitions of the SSB using a second transmission period that is different than the first transmission period, wherein the first transmission period and the second transmission period have durations greater than 1 second.
18 . The method of claim 17 , further comprising:
subsequent to transmission of the first burst of repetitions of the SSB, periodically transmitting, in the first signal beam and with the first transmission period, a first burst of repetitions of a first system information block (SIB); and
subsequent to transmission of the second burst of repetitions of the SSB, periodically transmitting, in the second signal beam and with the second transmission period, a second burst of repetitions of the first SIB.
19 . A method of operating a communications satellite to perform wireless communications with user equipment (UE) devices, the method comprising:
periodically transmitting, with a first transmission period, a first burst of repetitions of a system synchronization block (SSB), the first burst being transmitted in a first signal beam;
transmitting a system information block (SIB) that identifies a paging cycle for a given signal beam;
transmitting, during a user equipment (UE) device wake-up period associated with the paging cycle, a paging signal in the given signal beam;
transmitting, in the given signal beam, the SSB appended to the paging signal based on a duration between the UE device wake-up period and a previous transmission of the SSB in the given signal beam exceeding a threshold duration; and
transmitting the paging signal without the SSB appended to the paging signal based on the duration being less than the threshold duration.
20 . The method of claim 19 , further comprising:
periodically transmitting, with a second transmission period, a second burst of repetitions of the SSB, the second burst being transmitted in a second signal beam oriented at a different angle than the first signal beam.