Samsung Electronics Co., Ltd.

University System of Maryland

Min-Ho Shin

In-Sun Lee

William Albert Arbaugh

Arunesh Mishra

Kyung-Hun Jang

Hun-Kee Kim

Sang-Boh Yun

Sung-Jea Ko

Hwan-Min Kang

Hye-Soo Kim

Ki-Ho Kil

Gang-Mi Gil

Chang-Hyun Kwak

Kyuno-Hun Jang

T Charles Clancy

Kyung-Jun Jang

Kyung-Hun No 102-505 Dongsuwon Jang

An apparatus and a method for estimating a Doppler frequency in a mobile communication system are provided. The apparatus includes an estimator for temporarily estimating a maximum Doppler frequency based on channel values sampled according to a first period in a frame, a detector for calculating at least one correlation value between at least one channel value additionally sampled in the frame and at least one channel value sampled over the first period, and for determining whether aliasing occurs based on the correlation value, and a determiner for determining a final maximum Doppler frequency according to the occurrence or non-occurrence of the aliasing.

Apparatus and method for estimating doppler spread in mobile communication system

A method for minimizing handoff latencies when a handoff is performed in a wireless network. An access point (AP) or base station associated to a current wireless station (STA) allows information required for a reassociation to the STA to be propagated to handoff-capable neighboring APs or base stations. When the STA moves, a neighboring AP or base station performs the reassociation to the STA on the basis of context. When a handoff procedure is performed, the time taken to receive context of a corresponding STA is reduced, such that a fast handoff can be implemented.

Method for performing handoff in wireless network

An apparatus and method for rate dematching in a communication system are provided. The apparatus includes an input sequence generator, an error calculator, and a puncture/repetition determiner. The input sequence generator calculates if current input data among data, which are input in interleaved sequence, corresponds to any nsequence among before-interleaved sequence. The error calculator calculates an error for the current input data using the calculated sequence. The puncture/repetition determiner determines type of the current input data using the error for the current input data.

Apparatus and method for rate dematching in a communication system

A roaming service method for a fast and secure wireless network is provided. In an embodiment of the present invention, an AP, which an STA associates with, transmits proactive keys needed for roaming to neighbor APs of the AP. When the STA moves to one of the neighbor APs, a reassociation is carried out between the STA and the neighbor AP using the already provided proactive key. In another embodiment of the present invention, an authentication server transmits proactive keys needed for roaming to neighbor APs to which the STA is likely to move, so that when the STA moves to one of the neighbor APs, a reassociation is carried out between the STA and the neighbor AP using the already provided proactive key.

Method for fast roaming in a wireless network

The present invention relates to an authentication method for wireless distribution system including at least one base station providing access service to mobile stations in a coverage of the base station. In the authentication method, an unregistered base station receives an authentication request from a mobile station, multicast an identity request for identifying the mobile station over the wireless distribution system, receives identity responses from at least one base station in response to the identity request, and performs authentication of the mobile station on the basis of the identity responses. The distributed authentication method of the present invention is performed without AAA server, when a new base station is installed or isolated base stations are joined, such that it is possible to extend the network in an easy manner without degradation of the security degree and additional labor burden of the operator.

Authentication method for wireless distributed system

Disclosed is a method for managing mobility of mobile nodes between heterogeneous networks in an IP-based mobile communication system including a plurality of access nodes for providing an IP service to mobile nodes located in their service areas and a neighbor graph server for supporting connection to the access nodes by the mobile nodes. The method includes classifying the access nodes according to available service level; classifying the mobile nodes according to required service level, generating service level neighbor graphs each including access nodes supporting the same service level; generating a mapping table for mapping the mobile nodes to the neighbor graphs according to service level required by the mobile node; and supporting movement of a mobile node between networks using the neighbor graph and the mapping table.

Mobility management method using an improved neighbor graph

Provided is a probing method for handoff including constructing a group of neighbor access points of a current access point with which the station associated, generating subgroups of the neighbor access points by the channel assigned to the access points, probing the access points by subgroup in a subgroup selection order, and selecting the neighbor access point having best link quality as a target access point to handoff. The probing method of the present invention is implemented with a novel non-overlap graph for constructing the neighbor graph such that the probing latency is dramatically reduced, resulting in reduction of handoff delay.

Probing method for fast handoff in WLAN

A roaming service method for a fast and secure wireless network is provided. In an embodiment of the present invention, an AP, which an STA associates with, transmits security keys needed for roaming to neighbor APs of the AP. When the STA moves to one of the neighbor APs, a reassociation is carried out between the STA and the neighbor AP using the already provided security key. In another embodiment of the present invention, an authentication server transmits security keys needed for roaming to neighbor APs to which the STA is likely to move, so that when the STA moves to one of the neighbor APs, a reassociation is carried out between the STA and the neighbor AP using the already provided security key.

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Laurel, MD, United States of America

Min-Ho Shin