Carrier aggregation using shared spectrum
A method for performing Carrier Aggregation (CA) using spectrum shared between an incumbent user and a telecommunications network includes establishing a primary cell (PCell) for the secondary user in a portion of radio spectrum that is exclusively licensed to the telecommunications network, establishing a secondary cell (SCell) for the telecommunications network in a portion of the shared spectrum that is shared with the incumbent user, receiving schedule data for the incumbent user at a controller in communication with the incumbent user and a transmitter for the PCell and the SCell, scheduling transmissions for the PCell and the SCell to avoid interference to the incumbent user, and transmitting the scheduled transmissions through the PCell and the SCell using Carrier Aggregation (CA). Accordingly, one or more SCell in shared spectrum may be aggregated with a PCell in dedicated spectrum.
1. A method for performing Carrier Aggregation (CA) using spectrum shared between an incumbent user and a telecommunications network, the method comprising:
establishing a primary cell (PCell) for the telecommunications network in a portion of radio spectrum that is exclusively licensed to the telecommunications network;
establishing a secondary cell (SCell) for the telecommunications network in a portion of the shared spectrum that is shared with the incumbent user;
receiving schedule data for the incumbent user at a controller in communication with the incumbent user and a transmitter for the PCell and the SCell, the schedule data being based on a plurality of times and frequencies for future transmissions of the incumbent user;
using the schedule data to determine that a second frequency band is not occupied by incumbent user transmissions in the shared spectrum at a future time;
scheduling transmissions for the SCell in the second frequency band at the future time; and
transmitting the scheduled transmissions through the PCell and the SCell using Carrier Aggregation (CA),
wherein the controller receives the schedule data at least 60 Time Transmission Intervals (TTIs) in advance of the future time.
2. The method of claim 1 , wherein the schedule data for the incumbent user indicates interference from the SCell to the incumbent user, the method further comprising:
dynamically reconfiguring the SCell by moving the SCell from a first frequency band to the second frequency band at the future time to avoid the interference from the SCell to the incumbent user.
3. The method of claim 2 , further comprising:
determining a frequency band in the shared spectrum with the least chance of interfering with the incumbent user,
wherein the second frequency band is the frequency band with the least chance of interfering with the incumbent user.
4. The method of claim 2 , wherein the schedule data for the incumbent user includes a spectrum mask, the method further comprising:
using the spectrum mask to determine that the second frequency band has a lowest probability of interfering with incumbent user transmissions of frequency bands in the shared spectrum.
5. The method of claim 1 , wherein the schedule data is received by a central controller entity that coordinates scheduling between the incumbent user and the telecommunications network.
6. The method of claim 1 , wherein schedule data for the incumbent user is not transmitted to a scheduler for the primary and secondary cells.
7. The method of claim 1 , further comprising:
disabling unused secondary cells in the shared spectrum.
8. The method of claim 1 , wherein the bandwidth occupied by the PCell is half or less of the bandwidth occupied by the Scell.
9. The method of claim 1 , wherein the incumbent user uses a frequency hopping transmission pattern in the shared spectrum.
10. A telecommunications system that performs Carrier Aggregation using shared spectrum, the system comprising:
a controller with a communication channel to network equipment of an incumbent user of the shared spectrum, the controller receiving schedule data for the incumbent user over the communication channel and using the schedule data to determine that a second frequency band is not occupied by incumbent user transmissions in the shared spectrum at a future time, the schedule data being based on a plurality of times and frequencies for future transmissions of the incumbent user; and
a base station in communication with a user equipment (UE), the base station being operative to:
establish a primary cell (PCell) for the incumbent user in a portion of radio spectrum that is exclusively licensed to a telecommunications network;
establish a secondary cell (SCell) for the telecommunications network in a portion of the shared spectrum that is shared with the incumbent user; and
transmit the scheduled transmissions through the PCell and the SCell using Carrier Aggregation (CA),
wherein transmissions for the SCell are scheduled at the future time in the second frequency band, and
wherein the controller receives the schedule data at least 60 Time Transmission Intervals (TTIs) in advance of the future time.
11. The system of claim 10 , wherein, when the schedule data for the incumbent user indicates interference from the SCell to the incumbent user, the base station dynamically reconfigures the SCell by moving the SCell from a first frequency band to a second frequency band to avoid the interference from the SCell to the incumbent user.
12. The system of claim 11 , wherein the second frequency band is a frequency band with the least chance of interfering with the incumbent user.
13. The system of claim 11 , wherein the schedule data for the incumbent user includes a spectrum mask, and the controller uses the spectrum mask to determine that the second frequency band has a lowest probability of interfering with incumbent user transmissions of frequency bands in the shared spectrum.
14. The system of claim 10 , wherein the controller coordinates scheduling between the incumbent user and the base station.
15. The system of claim 10 , wherein schedule data for the incumbent user is not transmitted to a scheduler for the primary and secondary cells.
16. The system of claim 10 , wherein the base station disables unused secondary cells in the shared spectrum.
17. The system of claim 10 , wherein the bandwidth occupied by the PCell is half or less of the bandwidth occupied by the Scell.
18. The system of claim 10 , wherein the incumbent user uses a frequency hopping transmission pattern in the shared spectrum.
19. The method of claim 1 , wherein the incumbent user is a radar system.
20. The method of claim 19 , wherein actual transmission times and frequencies of the radar system are obfuscated for the telecommunications network.
21. A method for performing Carrier Aggregation (CA) using spectrum shared between an incumbent user and a telecommunications network, the method comprising:
establishing a primary cell (PCell) for the telecommunications network in a portion of radio spectrum that is exclusively licensed to the telecommunications network;
establishing a secondary cell (SCell) for the telecommunications network in a portion of the shared spectrum that is shared with the incumbent user;
receiving schedule data for the incumbent user at a controller in communication with the incumbent user and a transmitter for the PCell and the SCell, the schedule data being based on a plurality of times and frequencies for future transmissions of the incumbent user;
using the schedule data to determine that a second frequency band is not occupied by incumbent user transmissions in the shared spectrum at a future time;
determining a frequency band in the shared spectrum with the least chance of interfering with the incumbent user;
scheduling transmissions for the PCell and the SCell to avoid interference to the incumbent user at the future time;
dynamically reconfiguring the SCell by moving the SCell from a first frequency band to the second frequency band at the future time to avoid the interference from the SCell to the incumbent user; and
transmitting the scheduled transmissions through the PCell and the SCell using Carrier Aggregation (CA)
wherein the schedule data for the incumbent user indicates interference from the SCell to the incumbent user,
wherein the second frequency band is the frequency band with the least chance of interfering with the incumbent user, and
wherein the least interfered frequency band is determined using the following Equation 1:
f i =min i Σ j E T ( f i −f j )
in which f i is a channel index of the Scell in the shared spectrum, i=1, . . . , N, f j is a channel index of the incumbent user in the shared spectrum, j=1, . . . , M, and E T is a spectrum mask of the incumbent user.