Efficient rise over thermal (RoT) control during soft handover
View Patent ↗The invention relates to a method for communicating information relating to the scheduling of uplink data transmissions for a mobile terminal transmitting data on the uplink to a plurality of base stations during soft handover of the mobile terminal in a mobile communication system. Further at least one base station of said plurality of base stations schedules uplink data transmissions of the mobile terminal in soft handover. The different embodiments of the invention provide a communication system, a radio resource controller, a base station and mobile terminal which may perform different tasks of the method disclosed. To provide a method reducing the impact of uplink transmissions during soft handover on the rise over thermal it is suggested to provide all base stations communicating with the mobile terminal during soft handover with information on the maximum amount of resources allocated to the mobile terminal for uplink transmissions thereby allowing the base stations to schedule other terminal taking into account this information.
1. A method for communicating information relating to the scheduling of uplink data transmissions, wherein a mobile terminal transmits uplink data via an Enhanced Uplink Dedicated Channel (E-DCH) of a Universal Mobile Telecommunication System (UMTS) to a plurality of base stations during soft handover of the mobile terminal in a mobile communication system, and wherein at least one scheduling base station of said plurality of base stations schedules uplink data transmissions of the mobile terminal in soft handover, the method comprising:
determining, at the at least one scheduling base station of said plurality of base stations, scheduling information for the mobile terminal indicative of a maximum amount of uplink resources allocated to the mobile terminal for scheduled uplink data transmissions on the E-DCH by the mobile terminal,
transmitting, from the at least one scheduling base station, the scheduling information to at least one other base station of said plurality of base stations to inform the at least one other base station on the mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH,
scheduling, by the at least one other base station, at least one other mobile terminal in communication with a respective base station based on the information received from the at least one scheduling base station,
determining at the at least one scheduling base station new scheduling information for the mobile terminal indicative of a new allocated maximum amount of uplink resources allocated to the mobile terminal for uplink data transmission on the E-DCH,
signaling by the at least one scheduling base station the determined new scheduling information to the mobile terminal in soft handover to allocate to the mobile terminal the new maximum amount of uplink resources applicable on the E-DCH for uplink data transmissions, and
informing said other base stations on the allocated new amount of uplink resources, if a difference between the new mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH and the previous mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH is larger than a predetermined threshold value.
2. The method according to claim 1 , further comprising signaling by said at least one scheduling base station the determined scheduling information to the mobile terminal in soft handover to allocate the maximum amount of uplink resources to the mobile terminal for uplink data transmissions on the E-DCH.
3. The method according to claim 1 , wherein the maximum amount of uplink resources for uplink data transmissions on the E-DCH indicates the maximum data rate or the maximum uplink transmission power ratio that may be used by the mobile terminal for uplink transmissions using the E-DCH.
4. The method according to claim 2 , wherein the at least one scheduling base station schedules uplink data transmissions by controlling the Transport Format Combination Set (TFCS) available to the mobile terminal in soft handover for uplink data transmission or by controlling the uplink transmission power ratio of the mobile terminal.
5. The method according to claim 1 , wherein the scheduling information indicating the mobile terminal's maximum amount of uplink resources for uplink data transmission on the E-DCH is transported via a serving radio network controller, and
wherein indicating the mobile terminal's allocated maximum amount of uplink resources for uplink data transmission on the E-DCH comprises:
signaling the mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH from the at least one scheduling base station to the serving radio network controller, and
informing the mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH to the other base stations by the serving radio network controller.
6. The method according to claim 5 , wherein the serving radio network controller determines whether to forward the mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH to a respective one of said other base stations based on cell interference within the radio cell controlled by the respective one of said other base stations.
7. The method according to claim 1 , wherein the indicated mobile terminal's maximum amount of uplink resources for uplink data transmissions on the E-DCH for is transported using control signaling.
8. The method according to claim 1 , wherein the scheduling base station determines, signals and indicates the mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH for the mobile terminal in soft handover each time the mobile terminal in soft handover is scheduled by the scheduling base station.
9. The method according to claim 1 , further comprising receiving by the at least one scheduling base station information indicating the predetermined threshold value from a serving radio network controller.
10. The method according to claim 4 , wherein the plurality of base stations defines the active set of the mobile terminals in soft handover and
wherein the method further comprises adding a base station to the active set of the mobile terminals and signaling the mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH for the mobile terminal in soft handover to said added base station by the serving radio network controller.
11. The method according to claim 10 , wherein information for signaling of the mobile terminal's maximum amount of uplink resources for uplink data transmissions on the E-DCH to said added base station is comprised within a message communicated during the active set update procedure.
12. The method according to claim 1 , wherein one base station of said plurality of base stations schedules uplink data transmissions of the mobile terminal in soft handover to all base stations of said plurality of base stations.
13. The method according to claim 1 , wherein each of said base stations schedules uplink data transmissions of the mobile terminal in soft handover to the respective one of said plurality of base stations.
14. The method according to claim 13 , wherein each of the plurality of base stations determines scheduling information for the mobile terminal indicative of an allocated maximum amount of uplink resources for uplink data transmission on the E-DCH allocated to the mobile terminal by the respective base station, and signals the determined scheduling information to the mobile terminal in soft handover to allocate the maximum amount of uplink resources for uplink data transmissions using the E-DCH to the terminal for uplink data transmission to the respective base station.
15. The method according to claim 14 , further comprising choosing by the mobile terminal the lowest assigned maximum amount of uplink resources for uplink data transmissions using the E-DCH for uplink transmissions to all base stations of the plurality of base stations.
16. The method according to claim 15 , further comprising forming by the mobile terminal a combined maximum amount of uplink resources on the assigned maximum amounts of uplink resources for uplink data transmissions using the E-DCH, which is used by the mobile terminal for uplink transmissions to all base stations of the plurality of base stations.
17. The method according to claim 14 , wherein each of the plurality of base stations indicates its maximum amount of uplink resources for uplink data transmissions on the E-DCH allocated to the mobile terminal to a serving radio network controller and at least a subset of the plurality of base stations schedules at least one mobile terminal in communication with the respective base station taking into account a combined value or a lowest value of a maximum amount of uplink resources for uplink data transmissions on the E-DCH signaled to the respective base station from the serving radio network controller.
18. The method according to claim 17 , further comprising determining at the serving radio network controller a combined value or a lowest value of a maximum amount of uplink resources based on the maximum amounts of allocated resources indicated by the plurality of base stations and signaling the combined value or the lowest value of a maximum amount of uplink resources for uplink data transmissions on the E-DCH from the serving radio network controller to a subset of said plurality of base stations.
19. The method according to claim 18 , wherein the combined value or the lowest value of a maximum amount of uplink resources is signaled to those base stations having indicated a maximum amount of uplink resources for uplink data transmissions using the E-DCH different from the combined value or the lowest value.
20. The method according to claim 1 , further comprising requesting by a serving radio network controller from at least one base station of said plurality of base stations to signal the mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH for the mobile terminal in soft handover to said serving radio network controller.
21. The method according to claim 1 , wherein the maximum allocated amount of uplink resources for uplink data transmissions on the E-DCH is signaled from a base station to the mobile terminal via a shared channel or a dedicated channel.
22. The method according to claim 1 , wherein the uplink maximum transmission power ratio is a maximum power ratio of a data channel to a control channel for uplink transmissions.
23. A mobile communication system for communicating information relating to the scheduling of uplink data transmissions, wherein the communication system comprises:
a plurality of base stations; and
a mobile terminal that transmits uplink data on an Enhanced Uplink Dedicated Channel (E-DCH) of a Universal Mobile Telecommunication System (UMTS) to said plurality of base stations during soft handover of the mobile terminal in the mobile communication system,
wherein at least one scheduling base station of said plurality of base stations schedules uplink data transmissions of the mobile terminal in soft handover,
wherein the at least one scheduling base station of said plurality of base stations determines scheduling information for the mobile terminal indicative of an allocated maximum amount of uplink resources for the mobile terminal applicable to scheduled uplink data transmissions on the E-DCH by the mobile terminal and transmits scheduling information to at least one other base station of the plurality of base stations to inform the at least one other base station on the mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH, and
wherein the at least one other base station schedules at least one other mobile terminal in communication with a respective base station based on the scheduling information received from the at least one scheduling base station
wherein the at least one scheduling base station determines at new scheduling information for the mobile terminal indicative of a new allocated maximum amount of uplink resources allocated to the mobile terminal for uplink data transmission on the E-DCH,
wherein the at least one scheduling base station signals the determined new scheduling information to the mobile terminal in soft handover to allocate to the mobile terminal the new maximum amount of uplink resources applicable on the E-DCH for uplink data transmissions, and
wherein said other base stations are informed on the allocated new amount of uplink resources, if a difference between the new mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH and the previous mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH is larger than a predetermined threshold value.
24. The mobile communication system according to claim 23 , wherein the at least one scheduling base station transmits the determined scheduling information to the mobile terminal in soft handover to allocate the maximum amount of uplink resources for uplink data transmissions on the E-DCH to the mobile terminal.
25. The mobile communication system according to claim 24 , wherein the other base stations of said plurality of base stations schedule at least one other mobile terminal in communication with a respective base station taking into account the indicated mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH for said mobile terminal in soft handover.
26. A method for communicating information relating to the scheduling of uplink data transmissions, wherein a mobile terminal transmits uplink data via an Enhanced Uplink Dedicated Channel (E-DCH) of a Universal Mobile Telecommunication System (UMTS) to a plurality of base stations during soft handover of the mobile terminal in a mobile communication system, and wherein at least one scheduling base station of said plurality of base stations schedules uplink data transmissions of the mobile terminal in soft handover, the method comprising:
determining, at the at least one scheduling base station of said plurality of base stations, scheduling information for the mobile terminal indicative of a maximum amount of uplink resources allocated to the mobile terminal for scheduled uplink data transmissions on the E-DCH by the mobile terminal,
transmitting, from the at least one scheduling base station, the scheduling information to at least one other base station of said plurality of base stations to inform the at least one other base station on the mobile terminal's allocated maximum amount of uplink resources for uplink data transmissions on the E-DCH,
wherein each of said base stations schedules uplink data transmissions of the mobile terminal in soft handover to the respective one of said plurality of base stations,
wherein each of the plurality of base stations determines scheduling information for the mobile terminal indicative of an allocated maximum amount of uplink resources for uplink data transmission on the E-DCH allocated to the mobile terminal by the respective base station, and signals the determined scheduling information to the mobile terminal in soft handover to allocate the maximum amount of uplink resources for uplink data transmissions using the E-DCH to the terminal for uplink data transmission to the respective base station, and
wherein each of the plurality of base stations indicates its maximum amount of uplink resources for uplink data transmissions on the E-DCH allocated to the mobile terminal to a serving radio network controller and at least a subset of the plurality of base stations schedules at least one mobile terminal in communication with the respective base station taking into account a combined value or a lowest value of a maximum amount of uplink resources for uplink data transmissions on the E-DCH signaled to the respective base station from the serving radio network controller.
27. The method according to claim 26 , further comprising determining at the serving radio network controller a combined value or a lowest value of a maximum amount of uplink resources based on the maximum amounts of allocated resources indicated by the plurality of base stations and signaling the combined value or the lowest value of a maximum amount of uplink resources for uplink data transmissions on the E-DCH from the serving radio network controller to a subset of said plurality of base stations.
28. The method according to claim 27 , wherein the combined value or the lowest value of a maximum amount of uplink resources is signaled to those base stations having indicated a maximum amount of uplink resources for uplink data transmissions using the E-DCH different from the combined value or the lowest value.