Power control and power headroom reporting for dual connectivity

Patent metadata

Field	Value
Publication number	US-2016242128-A1
Application number	US-201415024807-A
Country	US
Kind code	A1
Filing date	Sep 4, 2014
Priority date	Sep 27, 2013
Publication date	Aug 18, 2016
Grant date	—

Abstract

The present disclosure relates to a method for efficiently performing power control in situations where the UE is connected to both a MeNB and SeNB. The MeNB determines a power distribution ratio for the power to be used by the UE for uplink transmission to the MeNB and SeNB, determines the parameters P EMAX,MeNB and P EMAX,SeNB and sends these parameters to the SeNB/UE for use in power control. Moreover, update of the power distribution ratio is performed by the MeNB with assistance by the UE, which provides the MeNB with information on the pathloss on the secondary radio link to the SeNB, preferably by transmitting a virtual power headroom report, regarding the secondary radio link to the SeNB, to the MeNB, from which the MeNB derives the information on the pathloss for the secondary radio link.

First claim

1 . A method for power headroom reporting in a mobile communication system, wherein a mobile station is connected via a first radio link to a master base station and at least to one secondary base station via a secondary radio link, the method comprising:
calculating by the mobile station a first power headroom report for the first radio link between the mobile station and the master base station; transmitting the calculated first power headroom report together with information allowing the master base station to determine information on the pathloss of the secondary radio link between the mobile station and the secondary base station, from the mobile station to the master base station; and calculating by the mobile station a secondary power headroom report for the secondary radio link between the mobile station and the secondary base station, and transmitting the calculated secondary power headroom report from the mobile station to the secondary base station.

2 . The method according to claim 1 , wherein the information, from which the master base station determines the information on the pathloss, is transmitted in form of a secondary virtual power headroom report for the secondary radio link between the mobile station and the secondary base station, the method further comprising:
calculating by the mobile station, the secondary virtual power headroom report for the secondary radio link between the mobile station and the secondary base station, based on a pre-configured virtual uplink resource assignment for said secondary radio link to the secondary base station.

3 . The method according to claim 1 , further comprising:
determining by the master base station an initial distribution of the available maximum transmit power of the mobile station between the master base station and the secondary base station, comprising determining a maximum output power of the mobile station for uplink transmissions to the master base station (PEMAX,MeNB) and a maximum output power of the mobile station for uplink transmissions to the secondary base station (PEMAX,SeNB); and transmitting the determined maximum output power of the mobile station for uplink transmissions to the secondary base station (PEMAX,SeNB), from the master base station to the secondary base station, preferably in a signaling message transmitted on the interface between the master and secondary base station, and the method further comprising: transmitting the determined maximum output power of the mobile station for uplink transmissions to the master base station (PEMAX,MeNB) and the determined maximum output power of the mobile station for uplink transmissions to the secondary base station (PEMAX,SeNB), from the master base station to the mobile station, preferably in a Radio Resource Control, RRC, message or in a Media Access Control, MAC, control element; or transmitting the determined maximum output power of the mobile station for uplink transmissions to the master base station (PEMAX,MeNB), from the master base station to the mobile station, preferably in a Radio Resource Control, RRC, message or in a Media Access Control, MAC, control element, and transmitting the determined maximum output power of the mobile station for uplink transmissions to the secondary base station (PEMAX,SeNB), from the secondary base station to the mobile station.

4 . The method according to claim 1 , wherein
when the mobile station determines that the secondary radio link between the mobile station and the secondary base station will become inactive for the uplink, the mobile station provides information to the master base station about the secondary radio link becoming inactive for the uplink, and preferably wherein the information, about the secondary radio link becoming inactive for the uplink, is provided to the master base station in the form of: a bit flag with a pre-determined value in the first power headroom report for the first radio link between the mobile station and the master base station; or a bit flag with a pre-determined value in the secondary virtual power headroom report for the secondary radio link between the mobile station and the secondary base station; or a pre-determined power headroom value of the secondary virtual power headroom report for the secondary radio link between the mobile station and the secondary base station.

5 . The method according to claim 4 , further comprising:
determining by the mobile station a length in time that the secondary radio link is expected to be inactive for the uplink, and wherein only in case the determined length in time exceeds a pre-determined length in time, the step of, the mobile station providing information to the master base station about the secondary radio link becoming inactive for the uplink, is performed.

6 . The method according to claim 4 , wherein the information, about the secondary radio link becoming inactive for the uplink, is provided to the master base station in the form of a pre-determined power headroom value of the secondary virtual power headroom report for the secondary radio link between the mobile station and the secondary base station, and
wherein the pre-determined power headroom value is a pre-determined negative value, preferably encoding time information about a length in time that the secondary radio link is expected by the mobile station to be inactive for the uplink.

7 . The method according to claim 4 , further comprising:
determining by the master base station an updated distribution of the available maximum transmit power of the mobile station between the master base station and the secondary base station, based on the received information about the secondary radio link becoming inactive for the uplink, comprising at least determining an updated value for the maximum output power of the mobile station for uplink transmissions to the master base station (PEMAX,MeNB); and transmitting by the master base station, the updated maximum output power of the mobile station for uplink transmissions to the master base station (PEMAX,MeNB), to the mobile station.

8 . The method according to claim 1 , wherein
when the mobile station determines that the first radio link between the mobile station and the master base station will become inactive for the uplink, the mobile station provides information to the secondary base station about the first radio link becoming inactive for the uplink, and preferably wherein the information, about the first radio link becoming inactive for the uplink, is provided to the secondary base station in the form of: a bit flag with a pre-determined value in the secondary power headroom report for the secondary radio link between the mobile station and the secondary base station; or a bit flag with a pre-determined value in the secondary virtual power headroom report for the secondary radio link between the mobile station and the secondary base station; or a pre-determined power headroom value of the secondary virtual power headroom report for the secondary radio link between the mobile station and the secondary base station.

9 . The method according to claim 8 , further comprising:
determining by the mobile station a length in time that the first radio link is expected to be inactive for the uplink, and wherein only in case the determined length in time exceeds a pre-determined length in time, the step of, the mobile station providing information to the secondary base station about the first radio link becoming inactive for the uplink, is performed.

10 . The method according to claim 8 , wherein the information, about the first radio link becoming inactive for the uplink, is provided to the secondary base station in the form of a pre-determ

Assignees

• Panasonic Ip Corp America

Inventors

• Loehr Joachim
• Suzuki Hidetoshi
• Basu Mallick Prateek

Classifications

• H04W52/367

  Power values between minimum and maximum limits, e.g. dynamic range · CPC title

• H04W76/15

  Setup of multiple wireless link connections · CPC title

• H04W52/365 Primary

  Power headroom reporting · CPC title

• H04W52/242

  taking into account path loss · CPC title

• H04W52/346 Primary

  distributing total power among users or channels · CPC title