Electronics and Telecommunications Research Institute

Samsung Electronics Co., Ltd.

Kt Corporation

Sk Telecom Company, Ltd.

Hanaro Telecom., Inc.

Ktfreetel Co., Ltd

Jae-Sun Cha

Chul-Sik Yoon

Kwang-Jae Lim

Sung-Cheol Chang

Disclosed is a handover method in a wireless portable Internet system. When a mobile subscriber station is in a drop state, a ranging request message including an identifier of a previous base station and a string generated by encoding the ranging request message using an authentication key of the previous base station is sent to a target base station. The target base station requests the previous base station to execute handover of the mobile subscriber station using the identifier of the previous base station included in the ranging request message. The previous base station carries out message authentication using the encoded string received from the target base station, and when the authentication is successful, transmits information about the mobile subscriber station that is required for handover to the target base station. Accordingly, a ceaseless service session can be provided even in the drop state.

Handover method in wireless portable internet system

The present invention relates to a handover method of a mobile station in a wireless communication system, and a base station and a mobile station for the same. A list of neighboring base stations that can accept a handover of a mobile station is shared by the mobile station and a serving base station before the mobile station performs the handover so as to reduce handover delay time in a high speed environment through addition, the active base station set managed by the mobile station and the serving base station can be managed with consideration of radio signal quality and resource state of each of the neighboring base stations included in the active base station set, and thus when the mobile station attempts a network re-entry process to a target base station that is not ready for the handover of the mobile station due to a loss of a handover control message, a handover failure due to a lack of radio resources can be prevented, thereby increasing a handover success rate.

Method of performing handover in wireless communication system

A method for measuring a position includes: allocating a first ranging code and a first ranging region for a mobile station; receiving a second ranging code and allocation information on a second ranging region of the mobile station from a neighboring base station; transmitting the first ranging code and the second ranging code to the mobile station; receiving the first ranging code from the mobile station in the first ranging region; calculating a received timing adjustment value of the first ranging code; receiving a received timing adjustment value of the second ranging code from the neighboring base station; and measuring the position of the mobile station according to the received timing adjustment value of the first ranging code and the received timing adjustment value of the second ranging code. Therefore, the cost and efficiency can be improved by measuring the position of the mobile station by changing the ranging method used in the conventional system.

Method for location determinating

Upper level protocol message transmitting method and apparatus are provided based on a new management message to be used in a portable Internet system. When a base station receives the upper level protocol message to be broadcast, it includes the same in the management message and transmits the included message to all the mobile terminals of a cell, and thus, the total number of the transmissions is decreased, thereby increasing a wireless efficiency.

Method and apparatus for upper level protocol message

In an Automatic Repeat reQuest (ARQ) method for recovering ARQ data by a target base station when handover of a mobile terminal is performed from a serving base station to the target base station in a portable Internet system is provided. First ARQ data, which includes a first service data unit (SDU), a first ARQ block sequence number, and a first sub-ARQ block sequence number, that are buffered in the serving base station are received and second ARQ data, which includes a second SDU, are received from the serving base station. The received first SDU is divided into ARQ blocks and is transmitted to the mobile terminal; and the received second SDU is divided into the ARQ blocks and is transmitted to the mobile terminal.

Growing community of inventors

Daejeon, South Korea

Jae-Sun Cha