Carrier aggregation inter eNB activation

1. A method for deciding on an activation of downlink carrier aggregation for a carrier of a first base station and a carrier of a second base station of a cellular network for delivering a service to a mobile terminal, the method being performed by the cellular network and comprising:

determining that the downlink carrier aggregation is to be activated for the mobile terminal, wherein the determining is performed on a basis of a combination of a plurality of parameters comprising:

at least one parameter associated with a performance of the cellular network, wherein the at least one parameter associated with the performance of the cellular network comprises an indication of latency for communication between network entities of the cellular network and a parameter based on an assessment of a change in throughput due to carrier aggregation relative to a change in transmission overheads due to carrier aggregation activation,

at least one parameter associated with a Quality of Service requirement of the service, wherein the at least one parameter associated with the Quality of Service requirement of the service comprises one or more of a latency requirement of the service or a minimum bit rate requirement of the service,

at least one parameter associated with a state of the mobile terminal, wherein the at least one parameter associated with the state of the mobile terminal comprises a quality of service state, and wherein the quality of service state for the mobile terminal indicates a maximum delay tolerance for the mobile terminal,

at least one parameter associated with a radio link between the mobile terminal and the first base station and/or second base station, and

at least one parameter associated with a rate of handover between base stations for the mobile terminal;

subsequent to the mobile terminal ratifying activation of the downlink carrier aggregation, receiving an indication from the mobile terminal, the indication indicating that the mobile terminal's ratifying of the downlink carrier aggregation is based on a battery condition of the mobile terminal such that the cellular network receives information describing the mobile terminal's battery conditional; and

deciding to activate carrier aggregation if the indication of latency is less than a threshold value;

deciding to activate carrier aggregation if the latency requirement of the service is at least a threshold delay tolerance level; and

deciding to activate carrier aggregation if the maximum delay tolerance for the mobile terminal is at least a threshold delay tolerance.

2. The method of claim 1 , wherein the at least one parameter associated with the state of the mobile terminal comprises one or more of:

a mobility state;

a quality of service state;

the battery condition; and

a transmission power back-off state.

3. The method of claim 2 , wherein the parameter associated with the mobility state is based on one or more of:

Doppler information from a mobile terminal transmission;

a time duration of attachment of the mobile terminal to a base station; and

a location for the mobile terminal.

4. The method of claim 2 , wherein the parameter associated with the mobility state indicates whether the mobile terminal is nomadic, the method further comprising deciding to activate carrier aggregation if the mobile terminal is nomadic.

5. The method of claim 2 , further comprising:

receiving the parameter associated with the battery condition at the cellular network from the mobile terminal; and

deciding to activate carrier aggregation if the parameter associated with the battery condition indicates that the battery power level is at least a threshold level or deciding not to activate carrier aggregation if the parameter associated with the battery condition indicates that the battery power level is less than the threshold level.

6. The method of claim 2 , wherein the transmission power back-off state indicates a transmission power back-off associated with carrier aggregation activation, the method further comprising:

assessing a throughput parameter for carrier aggregation activation based on the indicated transmission power back-off; and

deciding to activate carrier aggregation if the assessed throughput parameter is at least a threshold level.

7. The method of claim 1 , wherein the at least one parameter associated with the performance of the cellular network comprises a parameter based on an assessment of a change in throughput due to carrier aggregation activation relative to a change in transmission overheads due to carrier aggregation activation.

8. The method of claim 7 , further comprising deciding to activate carrier aggregation if the assessment indicates an increase in throughput due to carrier aggregation activation relative to the change in transmission overheads due to carrier aggregation activation.

9. The method of claim 1 , wherein the step of deciding on the activation of carrier aggregation is based on a weighted measure of the plurality of the parameters.

10. The method of claim 1 , wherein the parameter associated with the state of the mobile terminal is based on both:

a time duration of attachment of the mobile terminal to a base station; and

a location for the mobile terminal.

11. A computer program product having a non-transient computer readable medium having stored thereon executable code that, when executed by a processor is configured to carry out the method of claim 1 .

12. A network entity of a cellular network, configured to set an activation state for carrier aggregation based on a decision made in accordance with the method of claim 1 .