Methods and arrangements in a telecommunication system
The present invention relates to methods and arrangements in a multi-carrier system. It also assumes independent DRX (Discontinuous reception) functionality on respective component carriers and the possibility for one carrier, e.g. the anchor carrier to initiate a change of DRX state for another component carrier. The basic concept of the present invention is to introduce a new “dormant” state in the DRX logic, whereby the dormant state can be used for non-anchor carrier components. The dormant DRX state implies that a carrier of a UE having this state is not required to monitor system signaling. In embodiments of the present invention this new state is introduced for a particular component carrier (e.g. non-anchor component carrier) for a UE operating in a multi-carrier system, and how to perform the transitions to and from the dormant DRX state implicitly, e.g. based on configured timer(s) for the component carrier or explicit signaling in a different (e.g. anchor) component carriers.
1. A User Equipment, UE, connectable over multiple carriers to a network node of a wireless communication system wherein the UE is capable of discontinuous reception (DRX), the UE comprising:
a processor configured to enter a first DRX state on a non-anchor carrier of the multiple carriers where the UE does not monitor system signaling on the non-anchor carrier over multiple DRX cycles when in the first DRX state; and
a receiver configured to receive control information on an anchor carrier controlling transition between the first DRX state of the non-anchor carrier and a second DRX state of the non-anchor carrier where the UE is required to periodically monitor system signaling on the non-anchor carrier in the second DRX state;
wherein the anchor carrier is used for control signaling and system information, and
wherein the non-anchor carrier is only used to carry data.
2. The UE according to claim 1 further comprising:
a timer associated with a configurable time during which the UE has not received system information on the non-anchor carrier,
wherein the processor is adapted to configure the UE to transfer the non-anchor carrier between the first DRX state and the second DRX state based on timing of the timer, where the UE is required to periodically monitor system signaling on the non-anchor carrier in the second DRX state.
3. The UE according to 1 , wherein the receiver is configured to receive the control signaling on the anchor carrier over layer 1, layer 2 or layer 3.
4. The UE according to claim 1 wherein the non-anchor carrier is maintained in the first DRX state for multiple consecutive DRX cycles without monitoring system signaling on the non-anchor carrier.
5. The UE according to claim 4 wherein the non-anchor carrier is maintained in the first DRX state for multiple consecutive DRX cycles of the anchor carrier without monitoring system signaling on the non-anchor carrier.
6. The UE according to claim 1 wherein the control information is received on the anchor carrier to control a transition of the non-anchor carrier from the first DRX state where the UE does not monitor system signaling on the non-anchor carrier over multiple DRX cycles to the second DRX where the UE is required to periodically monitor system signaling on the non-anchor carrier.
7. A method in a User Equipment, UE, connectable over multiple carriers to a network node of a wireless communication system and capable of discontinuous reception (DRX), the method comprising:
entering a first DRX state on a non-anchor carrier of the multiple carriers where the UE does not monitor system signaling on the non-anchor carrier over multiple DRX cycles in the first DRX state; and
receiving control information on an anchor carrier controlling transition between the first DRX state and a second DRX state of the non-anchor carrier where the UE is required to periodically monitor system signaling on the non-anchor carrier in the second DRX state;
wherein the anchor carrier is used for control signaling and system information, and
wherein the non-anchor carrier is only used to carry data.
8. The method according to claim 7 , further comprising:
initiating a transition of the non-anchor carrier between the first DRX state and the second DRX state based on a timing of a timer associated with a configurable time during which the UE has not received system information on the non-anchor carrier.
9. The method according to claim 7 , further comprising:
receiving configuration parameters associated with the first DRX state,
wherein entering the first DRX state on the non-anchor carrier of the multiple carriers is performed based on the received configuration parameters.
10. The method according to claim 7 wherein the non-anchor carrier is maintained in the first DRX state for multiple consecutive DRX cycles without monitoring system signaling on the non-anchor carrier.
11. The method according to claim 10 wherein the non-anchor carrier is maintained in the first DRX state for multiple consecutive DRX cycles of the anchor carrier without monitoring system signaling on the non-anchor carrier.
12. The method according to claim 7 wherein the control information is received on the anchor carrier to control a transition of the non-anchor carrier from the first DRX state where the UE does not monitor system signaling on the non-anchor carrier over multiple DRX cycles to the second DRX where the UE is required to periodically monitor system signaling on the non-anchor carrier.