Implicit DRX cycle length adjustment control in LTE
A method for controlling discontinuous reception in a wireless transmit/receive unit includes defining a plurality of DRX levels, wherein each DRX level includes a respective DRX cycle length and transitioning between DRX levels based on a set of criteria. The transitioning may be triggered by implicit rules.
1. A wireless transmit receive unit (WTRU), the WTRU comprising a processor configured to:
receive a message comprising a DRX configuration from a base station, the DRX configuration comprising a first DRX cycle length, a second DRX cycle length, and an indication of a resume period, wherein the indication of a resume period indicates a number of DRX cycles at which the WTRU is to perform DRX using the first DRX cycle length prior to implicitly transitioning to performing DRX using the second DRX cycle length if no new transmissions are received;
perform DRX using the first DRX cycle length;
determine that the WTRU has performed DRX using the first DRX cycle length for the number of DRX cycles indicated by the resume period without receiving a new transmission; and
transition the WTRU from performing DRX using the first DRX cycle length to performing DRX using the second DRX cycle based on determining that the WTRU has performed DRX using the first DRX cycle length for the determined number of DRX cycles indicated by the resume period without receiving a new transmission, wherein the second DRX cycle length is a multiple of the first DRX cycle length.
2. The WTRU as in claim 1 , wherein the processor is further configured to monitor a control channel for reception of downlink commands.
3. The WTRU as in claim 1 , wherein a command received on a control channel causes the WTRU to change its DRX cycle length.
4. The WTRU as in claim 1 , further comprising performing DRX using the second DRX cycle length prior to performing DRX using the first DRX cycle length.
5. The WTRU as in claim 1 , wherein the message corresponds to a radio resource control (RRC) message, and the processor is configured to implement DRX operation at a Medium Access Control (MAC) level.
6. The WTRU as in claim 1 , wherein the message comprising the DRX configuration is received via higher layer signaling.
7. The WTRU as in claim 1 , wherein the processor is configured to determine to refrain from transitioning to performing DRX using the second DRX cycle length on condition that the WTRU receives a subsequent message from the base station while performing DRX using the first DRX cycle length.
8. The WTRU as in claim 7 , wherein the subsequent message is a command, and the WTRU is configured to operate using the first DRX cycle length based on the command.
9. A wireless transmit receive unit (WTRU), the WTRU comprising a processor configured to:
receive a message comprising a DRX configuration from a base station, the DRX configuration comprising a first DRX cycle length, a second DRX cycle length, and an indication of a resume period, wherein the indication of a resume period indicates a number of DRX cycles at which the WTRU is to perform DRX using the first DRX cycle length prior to implicitly transitioning to performing DRX using the second DRX cycle length if no new transmissions are received;
perform DRX using the second DRX cycle length;
receive a trigger;
perform DRX using the first DRX cycle length based on receiving the trigger;
determine that the WTRU has performed DRX using the first DRX cycle length for the number of DRX cycles indicated by the resume period without receiving a new transmission; and
transition the WTRU from performing DRX using the first DRX cycle length to performing DRX using the second DRX cycle based on determining that the WTRU has performed DRX using the first DRX cycle length for the determined number of DRX cycles indicated by the resume period without receiving a new transmission, wherein the second DRX cycle length is a multiple of the first DRX cycle length.
10. The WTRU as in claim 9 , wherein the second DRX cycle length is an integer power of two multiple of the first DRX cycle length.
11. The WTRU as in claim 9 , wherein the first and second DRX cycle lengths are selected from a set of DRX cycle lengths given by the equation DRX-cycle-len =L×2 n , wherein n=0, 1, 2, . . ., and L is the length of a shortest DRX cycle.
12. The WTRU as in claim 9 , wherein the second DRX cycle length is twice the first DRX cycle length.
13. The WTRU as in claim 9 , wherein the resume period is synchronized with a base station.
14. The WTRU as in claim 9 , wherein the processor is further configured to monitor a control channel for reception of downlink commands.
15. The WTRU as in claim 9 , wherein a command received on a control channel causes the WTRU to change its DRX cycle length.
16. A method implemented by a wireless transmit receive unit (WTRU), the method comprising:
the WTRU receiving a message comprising a DRX configuration from a base station, the DRX configuration comprising a first DRX cycle length, a second DRX cycle length, and an indication of a resume period, wherein the indication of a resume period indicates a number of DRX cycles at which the WTRU is to perform DRX using the first DRX cycle length prior to implicitly transitioning to performing DRX using the second DRX cycle length if no new transmissions are received;
the WTRU performing DRX using the second DRX cycle length;
the WTRU receiving a trigger;
the WTRU performing DRX using the first DRX cycle length based on receiving the trigger;
the WTRU determining that the WTRU has performed DRX using the first DRX cycle length for the number of DRX cycles indicated by the resume period without receiving a new transmission; and
the WTRU transitioning performing DRX using the first DRX cycle length to performing DRX using the second DRX cycle based on determining that the WTRU has performed DRX using the first DRX cycle length for the determined number of DRX cycles indicated by the resume period without receiving a new transmission, wherein the second DRX cycle length is a multiple of the first DRX cycle length.
17. The method as in claim 16 , wherein the second DRX cycle length is an integer power of two multiple of the first DRX cycle length.
18. The method as in claim 16 , wherein the WTRU monitors a control channel for reception of downlink commands.
19. The method as in claim 16 , wherein a command received on a control channel causes the WTRU to change its DRX cycle length.