| US 7,583,966 B2 | ||
| Mobile communications system, radio network controller, and active set control method | ||
| Yukio Haseba, Tokyo (Japan); Daisuke Kondo, Tokyo (Japan); Emiko Sakuma, Tokyo (Japan); Osami Nishimura, Tokyo (Japan); Hisashi Kawabata, Tokyo (Japan); and Motoya Iwasaki, Tokyo (Japan) | ||
| Assigned to NEC Corporation, Tokyo (Japan) | ||
| Filed on Mar. 20, 2006, as Appl. No. 11/378,250. | ||
| Claims priority of application No. 2005-099572 (JP), filed on Mar. 30, 2005. | ||
| Prior Publication US 2006/0223538 A1, Oct. 05, 2006 | ||
| Int. Cl. H04W 36/00 (2009.01) | ||
| U.S. Cl. 455—436 [455/438; 455/439; 455/67.11; 455/435.1; 455/443; 455/115.1; 455/67.14; 370/331; 709/200] | 8 Claims |
| 1. A mobile communications system including a mobile terminal, a plurality of base stations each of which sets up a radio
channel to the mobile terminal, and a radio network controller which is connected to each of the base stations and includes
an active set for the mobile terminal, which shows a list of cells in which the radio channel is being established to the
mobile terminal for handover, said mobile communication system wherein:
said mobile terminal transmits a radio channel setup request, when detecting signal power of a downlink reference signal from
a neighboring cell is higher than an active set addition threshold level, for requesting to establish the radio channel in
the neighboring cell and to add the neighboring cell to the active set of the mobile terminal;
said base station transmits a radio channel release request, when degradation of communication quality of an uplink signal
from the mobile terminal is detected in a predetermined condition, for requesting to release the radio channel from the mobile
terminal in own cell and to delete own cell from the active set of the mobile terminal;
said radio network controller, by receiving the radio channel release request, releases the radio channel for the mobile terminal
in the cell which relates to the radio channel release request and deletes the cell from the active set of the mobile terminal,
and then, upon receiving the radio channel set up request from the mobile terminal, ignores the radio channel set up request
if the radio channel setup request relates to the same cell which has been deleted from the active set of the same mobile
terminal transmitting the radio channel setup request and if the radio channel setup request is received before a predetermined
time has elapsed after deletion of the cell from the active set; and
wherein, after the radio network controller has deleted the cell from the active set of the mobile terminal by the radio channel
release request from the base stations, and then, upon receiving the radio channel set up request from the mobile terminal,
the radio network controller accepts the radio channel setup request and sets up the radio channel based on the radio channel
set up request and adds the cell to the active set of the mobile terminal if the radio channel set up request is received
after the predetermined time has elapsed after deletion of the cell from the active set even though the radio channel setup
request relates to the same cell which has been deleted from the active set of the same mobile terminal transmitting the radio
channel setup request.
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