Method for accessing a cell using two pilot channels in a CDMA communication system of an asynchronous or quasi-synchronous mode

• US 6,205,132 B1
• Filed: 02/21/1997
• Issued: 03/20/2001
• Est. Priority Date: 02/22/1996
• Status: Expired due to Term

• Current Assignee: SK Telecom Co., Ltd.
• Original Assignee: Korea Mobile Telecommunications Corp.
• Inventors: Kim, Dong Ho, Choi, An Na, Park, Yong Wan, Yang, Yeon Dae, Ryu, Seong Moon, Ahn, Byeong Chul, Hong, Een Kee, Lee, Tae Young
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): LEE, CHI HO A
• Application Number:
  US08/803,995
• Time in Patent Office: 1,488 Days
• Field of Search: 370/320, 370/331, 370/335, 370/342, 370/349, 370/350, 370/355, 370/548, 370/519, 370/324, 370/332, 370/338, 455/422, 455/436, 455/438, 455/442, 455/450, 455/455, 455/444, 455/449, 455/502, 455/560, 455/513, 455/456, 455/556, 455/566, 455/437, 375/200, 375/206, 375/208
• US Class Current: 370/342
• CPC Class Codes: H04B 1/70775 Multi-dwell schemes, i.e. multiple accumulation times
• CPC Class Codes: H04B 1/7083 Cell search, e.g. using a three-step approach
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects

Abstract

The present invention discloses a method for accessing a cell, and more particularly, to a method for acquiring an initial synchronization using two pilot channels in a CDMA (Code Division Multiple Access) communication system of an asynchronous or quasi-synchronous mode. In accordance with the present invention, a CDMA communication system of an quasi-synchronous mode comprises the steps of synchronizing the mobile station with a cluster pilot, and searching for cell pilots on the basis of the cluster synchronization channel set up by the cluster pilot, and synchronizing the mobile station with the cell pilot having a maximum sensitivity, whereby the mobile station is synchronized with the base station through the cluster pilot and the cell pilot. Also, in accordance with the present invention, a CDMA communication system of a asynchronous mode comprises the steps of synchronizing the mobile station with a cluster pilot, and searching for all cell pilots in a cluster of which synchronization has been set up by the cluster pilot, and synchronizing the mobile station with the cell pilot having a maximum sensitivity, whereby the mobile station is synchronized with the base station through the cluster pilot and the cell pilot.

Claims

1. In a CDMA communication system including base stations, a base station controller and mobile stations, and discriminating the base stations by using different sequences, wherein the base station receives a synchronization signal from the base station controller, a method for accessing a cell, the method comprising the steps of:

synchronizing the mobile station with a cluster pilot representing a cluster which is a group of cells; and

searching for cell pilots each representing a cell on the basis of the cluster synchronization channel set up by the cluster pilot, and synchronizing the mobile station with the cell pilot having a maximum sensitivity,

whereby the mobile station is synchronized with the base station through the cluster pilot and the cell pilot.

2. In a CDMA communication system with a multi-layer structure, wherein the system includes base stations, a base station controller and mobile stations, and discriminates the base stations using different sequences, and wherein the base station receives a synchronization signal from the base station a controller, a method for accessing a cell in the mobile stations, the method comprising the steps of:

searching for cluster pilot sequences each representing a cell which is a group of cells until an output from a correlator is larger than a predetermined value, and searching for the remaining cluster pilot sequences on the basis of a current synchronization so that the mobile station sets up a cluster synchronization to the cluster pilot sequence having a maximum sensitivity;

reading a cluster synchronization channel set up by the cluster pilot sequence indicating the maximum sensitivity, and then reading cell pilot sequences each representing cells included in and a frequency band allocated to a cell pilot; and

searching for cell pilot sequences on the basis of the cluster synchronization channel so that the mobile station sets up a cell synchronization to the cell pilot sequence having a maximum sensitivity.

3. In a CDMA communication system including base stations, a base station controller and mobile stations, and discriminating the base stations using different sequences, wherein the base station receives a synchronization signal from the base station controller, and wherein the system transmits cluster pilots representing a cluster which is a group of cells in a center of the cluster, a method for accessing a cell in said mobile stations, the method comprising the steps of:

searching for cluster pilot sequences until an output from a correlator is larger than a predetermined value, and searching for the remaining cluster pilot sequences on the basis of a current synchronization so that the mobile station sets up a cluster synchronization of the cluster pilot sequence having a maximum sensitivity;

reading a cluster synchronization channel set up by the cluster pilot sequence indicating the maximum sensitivity, and then reading cell pilots; and

searching for cell pilot sequences each representing a cell on the basis of the cluster synchronization so that the mobile station sets up a cell synchronization to the cell pilot sequence having a maximum sensitivity.

4. In a CDMA communication including base stations, a base station controller and mobile stations, and discriminating the base stations using different sequences, wherein the base station receives a synchronization signal from the base station controller, and wherein all cells of the base stations transmit cluster pilot and cell pilots, the mobile stations for accessing a cell, a method for accessing a cell in the mobile stations, the method comprising the steps of:

searching for cluster pilot sequences each representing a cluster which is a group of cells so that the mobile station sets up a point of time of a synchronization to the cluster pilot sequence having a maximum sensitivity, and searching for the remaining cluster pilot sequences on the basis of a current synchronization so that the mobile station sets up a cluster synchronization to the cluster pilot sequence having a maximum sensitivity;

reading a cluster synchronization channel set up by the cluster pilot sequence indicating the maximum sensitivity, and then reading cell pilot sequences; and

searching for cell pilot sequences each representing a cell on the basis of the cluster synchronization so that the mobile station sets up a cell synchronization to the cell pilot sequence having a maximum sensitivity.

5. In a CDMA communication system including base stations, a base station controller and mobile stations, and discriminating the base stations using different sequences, a method for accessing a cell, the method comprising the steps of:

synchronizing the mobile station with a cluster pilot representing a cluster which is a group of cells; and

searching for all cell pilots each representing a cell in the cluster of which synchronization has been set up by the cluster pilot, and synchronizing the mobile station with the cell pilot having a maximum sensitivity,

whereby the mobile station is synchronized with the base station through the cluster pilot and the cell pilot.

6. In a CDMA communication system with a multi-layer structure, wherein the system includes base stations, a base station controller and mobile stations, and discriminates the base stations using different sequences, the mobile stations for accessing a cell, a method for accessing a cell in the mobile stations, the method comprising the steps of:

search for all cluster pilot sequences each representing a cluster which is a group of cells so that the mobile station sets up a cluster synchronization to the cluster pilot sequence having a maximum sensitivity;

reading a cluster synchronization channel set up by the cluster pilot sequence indicating the maximum sensitivity, and then reading cell pilot sequences and a frequency band allocated to a cell pilot; and

searching for all cell pilot sequences each representing a cell in a cluster of which synchronization is set up so that the mobile station sets up a cell synchronization to the cell pilot sequence having a maximum sensitivity.

7. In a CDMA communication system including base stations, a base station controller and mobile stations, and discriminating the base stations using different sequences, wherein the base station receives a synchronization signal from the base station controller, and wherein the system transmits cluster pilots in a center of a cluster, a method for accessing a cell in the mobile stations, the method comprising the steps of:

searching for all cluster pilot sequences each representing a cluster which is a group of cells so that the mobile station sets up a cluster synchronization to the cluster pilot sequence having a maximum sensitivity;

reading a cluster synchronization channel set up by the cluster pilot sequence indicating the maximum sensitivity, and then reading cell pilot sequences and a frequency band allocated to a cell pilot; and

searching for all cell pilot sequences each representing a cell in a cluster of which synchronization is set up so that the mobile station sets up a cell synchronization to the cell pilot sequence having a maximum sensitivity.

8. In a CDMA communication system including base stations, a base station controller and mobile stations, and discriminating the base stations using different sequences, wherein the base station receives a synchronization signal from the base station controller, and wherein all cells of the base stations transmit cluster pilots each representing a cluster which is a group of cells and cell pilots each representing a cell, the mobile stations for accessing a cell, a method for accessing a cell in said mobile stations, the method comprising the steps of:

searching for all cluster pilot sequences so that the mobile station sets up a cluster synchronization to the cluster pilot sequence having a maximum sensitivity;

reading a cluster synchronization channel set up by the cluster pilot sequence indicating the maximum sensitivity, and then reading cell pilot sequences and a frequency band allocated to a cell pilot; and

searching for all cell pilot sequences in a cluster of which synchronization is set up so that the mobile station sets up a cell synchronization to the cell pilot sequence having a maximum sensitivity.

9. In a CDMA communication system including base stations, a base station controller and mobile stations, and discriminating the base station by using different sequences, a method for accessing a cell, the method comprising the step of:

transmitting two pilots, wherein a first pilot represents a cluster which is a group of cells and a second pilot represents a cell.

10. In a CDMA communication system including base stations, a base station controller and mobile stations, and discriminating the base station by using different sequences, a method for accessing a cell, the method comprising the steps of:

grouping at least two cells as a cluster;

synchronizing a mobile station with a cluster pilot representing a cluster which is a group of cells; and

searching for all cell pilots each representing a cell included in the cluster of which synchronization has been set up by the cluster pilot, and synchronizing the mobile station with the cell pilot having a maximum sensitivity.

11. In a CDMA communication system including base stations, a base station controller and mobile stations, and discriminating the base station by using different sequences, a method for accessing a cell, the method comprising the steps of:

transmitting, at the base station, a cluster pilot channel and a cell pilot channel, wherein the cluster pilot channel represents a cluster which is a group of cells and the cell pilot channel represents a cell;

synchronizing a mobile station with said cluster pilot; and

searching for all of the cell pilots included in said cluster of which synchronization has been set up by said cluster pilot, and synchronizing the mobile station with the cell pilot having maximum sensitivity.