Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
2000-07-06
2003-05-27
Le, Thanh Cong (Department: 2684)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S440000, C370S320000, C370S321000
Reexamination Certificate
active
06571098
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a device and a method for mobile radio communication, and in particular, to a mobile radio communication system, a mobile radio communication method and a base station controller employing data selection process.
DESCRIPTION OF THE PRIOR ART
Mobile stations such as portable cellular phones have become widely available these days, and mobile stations according to CDMA (Code Division Multiple Access) have been popular today because of their fine speech quality.
FIG. 1
shows an example of a CDMA mobile radio communication system. The mobile communication system shown in
FIG. 1
includes a mobile station (MS)
101
, radio base stations (BS's)
102
A,
102
B,
102
C and
102
D, base station controllers (BSCs)
104
and
105
, and a mobile services switch center (MSC)
108
. The radio base stations
102
A,
102
B,
102
C and
102
D take charge of mobile service areas
103
A,
103
B,
103
C and
103
D, respectively. The radio base stations
102
A and
102
B are connected to the base station controller
104
, and the radio base stations
102
C and
102
D are connected to the base station controller
105
.
In the CDMA mobile radio communication system of
FIG. 1
, upstream data which is transmitted by the mobile station
101
which is located in the mobile service areas
103
A and
103
B is received by the radio base stations
102
A and
102
B, and the radio base stations
102
A and
102
B send the received data to the base station controller
104
. The base station controller
104
which receives the upstream data of the mobile station
101
from the radio base stations
102
A and
102
B executes “selection process for diversity hand-over” with regard to the received upstream data, according to timing which is provided in sync with radio frames. In the selection process, the base station controller
104
selects the upstream data from the radio base station
102
A or the upstream data from the radio base station
102
B based on radio quality information which is supplied from the radio base stations
102
A and
102
B. After the selection process is finished, the base station controller
104
sends the selected upstream data to the mobile services switch center
108
.
However, if there is a difference of data transmission time between the line from the radio base station
102
A to the base station controller
104
and the line from the radio base station
102
B to the base station controller
104
(for example, if the data transmission from the radio base stations
102
A and
102
B to the base station controller
104
is executed by means of ATM (Asynchronous Transfer Mode) data transmission and variations in cell delay occur), the base station controller
104
has to execute the selection process after waiting for the slowest upstream data corresponding to the longest data transmission time. While the base station controller
104
waits for the slowest upstream data, faster upstream data have to be temporarily stored in a buffer of the base station controller
104
, thereby processing delay due to the data buffering occurs.
Further, when the mobile station
101
, which has been located in the mobile service areas
103
A and
103
B and executing communication with the radio base stations
102
A and
102
B under the base station controller
104
(anchor-side base station controller (that is, a base station controller which started the communication with the mobile station
101
first)), moves into other mobile service areas
103
C and
103
D and starts communication with other radio base stations
102
C and
102
D under another base station controller
105
(drift-side base station controller) as shown in
FIG. 1
, a large number of connections become necessary if connections are established from the anchor-side base station controller
104
to all the radio base stations
102
C and
102
D which are communicating with the mobile station
101
under the drift-side base station controller
105
. Therefore, in such cases, the selection process is executed first in the drift-side base station controller
105
and only the selected upstream data is sent to the anchor-side base station controller
104
, and thereafter the selection process is executed again in the anchor-side base station controller
104
.
However, in the above method employing two stages of selection processes at the drift-side base station controller
105
and the anchor-side base station controller
104
, much data buffering time occurs in the drift-side base station controller
105
and the anchor-side base station controller
104
, and thereby delay is caused in the mobile radio communication service.
SUMMARY OF THE INVENTION
It is therefore the primary object of the present invention to provide a mobile radio communication system, a mobile radio communication method and a base station controller employing the selection process for diversity hand-over, by which the wait delay for the selection process in the case of the inter-BSC (Base Station Controller) handover can be decreased and thereby the processing delay can be minimized.
In accordance with a first aspect of the present invention, there is provided a mobile radio communication system comprising: mobile stations; radio base stations which communicate with the mobile stations via connections on radio waves; base station controllers for controlling radio base stations thereunder, each of which including an upstream selection process section for executing a selection process, in which received upstream data which have been transmitted by a mobile station and supplied from radio base stations thereunder to the base station controller are temporarily stored in a buffer and data having the highest quality is selected from the stored upstream data corresponding to the same radio frame based on radio quality information and the selected data having the highest quality is sent to the next upper device; and mobile services switch centers each of which is provided as the interface between a network and base station controllers which are connected thereunder. In the mobile radio communication system, the operation mode of the upstream selection process section of the base station controller can be set to through mode with respect to a mobile station. When the operation mode of an upstream selection process section of a base station controller is the through mode with respect to a mobile station and the upstream selection process section received upstream data transmitted by the mobile station from a radio base station thereunder or a lower base station controller which is communicating with the base station controller, the upstream selection process section directly sends the received upstream data to the next upper device without temporarily storing the received upstream data and executing the selection process.
In accordance with a second aspect of the present invention, in the first aspect, the operation mode of the upstream selection process section of the base station controller is set to normal mode with respect to a mobile station and thereby the selection process is executed normally with respect to the mobile station when a communicating connection number with respect to the mobile station, which means the number of radio base stations and lower base station controllers which are communicating with the base station controller with respect to the mobile station, is 2 or more. The operation mode of the upstream selection process section is set to the through mode with respect a mobile station when the communicating connection number with respect to the mobile station is 1.
In accordance with a third aspect of the present invention, in the first aspect, when a mobile station, which has been executing communication in a mobile service area of a radio base station under a first base station controller, moved and started communication with another radio base station under a second base station controller, the operation mode of the upstream selection process section of the second base station controller i
Dickstein Shapiro Morin & Oshinsky LLP.
NEC Corporation
Nguyen Huy D
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