Patents by Inventor Yoon Chae Cheong
Yoon Chae Cheong has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7388852Abstract: The present invention provides a fast and efficient retransmission technique, which allows a link control layer to request retransmission of frames upon receiving information from an underlying physical layer that an unsuccessful attempt to transmit data was detected. In general, a failed attempt to transmit a frame is detected at a physical layer of a receiver. In response, the physical layer of the receiver sends a message to a link control layer of the receiver to indicate the failed attempt to transmit a frame was detected. Upon receipt of the message, the link control layer sends a retransmission message to a corresponding link control layer of a sender. The retransmission message is configured to cause the sender to retransmit the unrecoverable data associated with the corrupted frame.Type: GrantFiled: December 13, 2001Date of Patent: June 17, 2008Assignee: Nortel Networks LimitedInventors: Hang Zhang, Mo-Han Fong, Mark Earnshaw, Wei Huang, Yoon Chae Cheong
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Patent number: 7383057Abstract: The present invention provides cyclic power changing patterns for transmissions in different sectors of a cellular system. The cyclic power changing patterns define unique patterns in which transmission power levels change over a period of time slots or within a group of sub-carriers. Each sector has a unique pattern, so that interference information monitored by the user elements, which are supported by base stations, are indicative of the interference contributions from adjacent sectors. Based on these interference contributions and the cyclic power changing patterns associated with these sectors, the base stations can schedule transmissions to the user elements during time slots or in sub-carriers to minimize the impact of interference from the adjacent sectors and to efficiently support dynamic needs of the individual user data packets according to QoS requirements.Type: GrantFiled: May 18, 2004Date of Patent: June 3, 2008Assignee: Nortel Networks LimitedInventors: Gamini Senarath, Yoon Chae Cheong, Shalini Periyalwar
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Patent number: 7342901Abstract: A wireless communication system (100) includes a network (102), one or more mobile stations (103), and a medium access control (MAC) protocol (201). The MAC protocol (201) includes a state transition design (400) and a control channel design (500). The state transition design (400) includes null (401), dormant (402), standby (403), and active states (404) for each mobile station (103). The control channel design (500) includes a common control channel (501), a slow control channel (502) and a fast control channel (503), and is adapted to control communications from the network to each mobile station.Type: GrantFiled: April 4, 2002Date of Patent: March 11, 2008Assignee: Nortel Networks LimitedInventors: Hang Zhang, Gamini Senarath, Mo-Han Fong, Bassam Hashem, Yoon Chae Cheong
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Publication number: 20080032696Abstract: Handover in a mobile communication system, and more particularly, an apparatus and method that can broadcast handover information to a particular region using beamforming is provided. An apparatus for storing handover information in a mobile communication system includes: an estimation unit to estimate a direction of arrival (DOA) of a received signal with respect to a first base station based on the received signal, wherein the received signal is received from a terminal belonging to the first base station; and a storage unit to store the estimated DOA as handover information associated with a second base station when the terminal is handed over to the second base station. According to aspects of the present invention, a number of neighboring base stations that a terminal needs to search to perform handover may be reduced. Therefore, the terminal may perform handover more quickly and a communication disconnection time may be reduced.Type: ApplicationFiled: October 9, 2007Publication date: February 7, 2008Applicant: Samsung Electronics Co., Ltd.Inventors: Hyun Ho CHOI, In Sun Lee, Hyo Sun HWANG, Yoon Chae CHEONG, Tae In Hyon, Kyung Hun Jang, Young Soo Kim
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Patent number: 7301950Abstract: The present invention provides an access point, such as a base station, facilitating wireless communications with a plurality of mobile terminals, which are capable of operating in an active or standby mode. The access point provides active-to-standby transition timers for controlling when to instruct active mobile terminals to enter a standby mode after the end of a communication session. The active-to-standby transition timers have variable values based on one or more Quality of Service (QoS) parameters. Different mobile terminals may be associated with different QoS levels. The values for the active-to-standby transition timers may vary based on their respective QoS levels. The initial values for the active-to-standby transition timers may differ depending on the QoS level for the associated mobile terminal. As the QoS parameters indicate conditions adversely affecting QoS, the active-to-standby timer values may decrease in proportion to the QoS parameters.Type: GrantFiled: February 14, 2002Date of Patent: November 27, 2007Assignee: Nortel Networks LimitedInventors: Yoon Chae Cheong, Gamini Senarath, Hang Zhang
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Patent number: 7289427Abstract: A method and apparatus are provided for error correction in a communication system employing Orthogonal Frequency Division Multiplexing. When a remote unit receives an OFDM symbol, a retransmission indicator bit is examined to determine whether the symbol is an original symbol or a retransmitted symbol. If it is a retransmitted symbol and the remote unit has a corresponding symbol stored in memory, then the received symbol is soft-combined with the stored symbol. Each packet in the symbol, either the received symbol if original or the soft-combined symbol if retransmitted, is examined by the remote unit. If the remote unit determines that a particular packet is intended for the remote unit, but can not determine the contents of the payload of the packet, the remote unit sends a retransmission request to the base station for retransmission of the symbol.Type: GrantFiled: September 6, 2006Date of Patent: October 30, 2007Assignee: Nortel Networks LimitedInventors: David G. Steer, Shalini S. Periyalwar, Koon Hoo Teo, Yoon Chae Cheong, Bassam M. Hashem
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Publication number: 20070142045Abstract: A method and apparatus for reducing signal interference within a cellular radio system to increase both coverage and capacity. The method and apparatus include altering the direction of beams within cell sectors is among discrete angular positions according to a predetermined, cyclic pattern. The predetermined, cyclic pattern varies in a group of adjacent cell sectors such that inter-cell interference is significantly reduced or eliminated by rotating at a different cycle the beams in adjacent cells. This discrete, angular movement of beams provides for downlink transmissions to be timed in such a way (i.e., scheduled) such that transmission to a user will occur in accordance with the beam and time slot having the best carrier to interference (C/I) ratio for that user.Type: ApplicationFiled: February 27, 2007Publication date: June 21, 2007Applicant: NORTEL NETWORKS LIMITEDInventors: Nimal SENARATH, Yoon Chae CHEONG, Shalini PERIYALWAR, Robert MATYAS
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Patent number: 7218891Abstract: A multi-hop relaying method and apparatus used in a cellular network. The multi-hop transmission scheme utilizes intelligent relays within a conventional cellular system having at least one base station, one or more intelligent relays, and user equipment elements. The method includes selecting the strongest pilot signal from among the base stations and intelligent relays, reporting such to the base station, distributing an active user list to the relays along with scheduling and routing information via a relay control channel, and transmitting data according to a respective active user based upon the pilot signal strength to maximize coverage and capacity over the cellular system.Type: GrantFiled: July 14, 2003Date of Patent: May 15, 2007Assignee: Nortel Networks LimitedInventors: Shalini Periyalwar, Yoon Chae Cheong, Nimal Senarath
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Patent number: 7203520Abstract: A method and apparatus for reducing signal interference within a cellular radio system to increase both coverage and capacity. The method and apparatus include altering the direction of beams within cell sectors is among discrete angular positions according to a predetermined, cyclic pattern. The predetermined, cyclic pattern varies in a group of adjacent cell sectors such that inter-cell interference is significantly reduced or eliminated by rotating at a different cycle the beams in adjacent cells. This discrete, angular movement of beams provides for downlink transmissions to be timed in such a way (i.e., scheduled) such that transmission to a user will occur in accordance with the beam and time slot having the best carrier to interference (C/I) ratio for that user.Type: GrantFiled: September 30, 2003Date of Patent: April 10, 2007Assignee: Nortel Networks LimitedInventors: Nimal Gamini Senarath, Yoon Chae Cheong, Shalini Periyalwar, Robert Matyas
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Patent number: 7110351Abstract: A method and apparatus are provided for error correction in a communication system employing Orthogonal Frequency Division Multiplexing. When a remote unit receives an OFDM symbol, a retransmission indicator bit is examined to determine whether the symbol is an original symbol or a retransmitted symbol. If it is a retransmitted symbol and the remote unit has a corresponding symbol stored in memory, then the received symbol is soft-combined with the stored symbol. Each packet in the symbol, either the received symbol if original or the soft-combined symbol if retransmitted, is examined by the remote unit. If the remote unit determines that a particular packet is intended for the remote unit, but can not determine the contents of the payload of the packet, the remote unit sends a retransmission request to the base station for retransmission of the symbol.Type: GrantFiled: December 19, 2000Date of Patent: September 19, 2006Assignee: Nortel Networks LimitedInventors: David G. Steer, Shalini S. Periyalwar, Koon Hoo Teo, Yoon Chae Cheong, Bassam M. Hashem
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Patent number: 7058085Abstract: A radio link protocol for a communications system ensures that delivery of Internet protocol data packets occurs within a set delay bound for the packets, in order to satisfy specified quality of service levels. Data packets arriving at a transmitter are subdivided into data blocks. As each block is transmitted, the transmitter starts an associated acknowledgement timer. The timer is turned off, before it expires, if the transmitter timely receives from a receiver a message informing the transmitter that the associated block was successfully received. If such message is not received, the timer expires and the transmitter sends an acknowledgement request signal to the receiver and starts an associated panic timer. The panic timer is turned off, before it expires, if the transmitter subsequently timely receives a message that the associated block was successfully received.Type: GrantFiled: March 14, 2001Date of Patent: June 6, 2006Assignee: Nortel Networks LimitedInventors: Mark Earnshaw, Yoon Chae Cheong, Wei Huang
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Patent number: 6885679Abstract: Methods, receivers and transmitters all adapted to assist in the performance of layer 2 frame delineation are provided which are applicable in the context of OFDM, and also applicable to any layer 1 design facilitating high data rate transmission. Advantageously, the invention allows the identification of where a layer 2 frame begins notwithstanding the fact that the previous layer 2 header, which would normally be used to identify the location of the next layer 2 frame, has been received in error. As a consequence, rather than discarding considerable quantities of data after an erroneous header, for example all data until a super-frame boundary, layer 2 frames can be correctly received staring with the next header received in a non-erroneous layer 1 frame.Type: GrantFiled: September 29, 2000Date of Patent: April 26, 2005Assignee: Nortel Networks LimitedInventors: Yoon Chae Cheong, Bassam M. Hashem, Shalini S. Periyalwar
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Publication number: 20040192204Abstract: A multi-hop relaying method and apparatus used in a cellular network. The multi-hop transmission scheme utilizes intelligent relays within a conventional cellular system having at least one base station, one or more intelligent relays, and user equipment elements. The method includes selecting the strongest pilot signal from among the base stations and intelligent relays, reporting such to the base station, distributing an active user list to the relays along with scheduling and routing information via a relay control channel, and transmitting data according to a respective active user based upon the pilot signal strength to maximize coverage and capacity over the cellular system.Type: ApplicationFiled: July 14, 2003Publication date: September 30, 2004Inventors: Shalini Periyalwar, Yoon Chae Cheong, Nimal Senarath
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Publication number: 20030112759Abstract: The present invention provides a fast and efficient retransmission technique, which allows a link control layer to request retransmission of frames upon receiving information from an underlying physical layer that an unsuccessful attempt to transmit data was detected. In general, a failed attempt to transmit a frame is detected at a physical layer of a receiver. In response, the physical layer of the receiver sends a message to a link control layer of the receiver to indicate the failed attempt to transmit a frame was detected. Upon receipt of the message, the link control layer sends a retransmission message to a corresponding link control layer of a sender. The retransmission message is configured to cause the sender to retransmit the unrecoverable data associated with the corrupted frame.Type: ApplicationFiled: December 13, 2001Publication date: June 19, 2003Inventors: Hang Zhang, Mo-Han Fong, Mark Earnshaw, Wei Huang, Yoon Chae Cheong
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Publication number: 20030096597Abstract: The present invention provides a scheduler capable of maximizing aggregate throughput while achieving controlled amount of fairness among users and meeting Quality of Service (QoS) requirements. The scheduler is configured to select the next unit of data to transmit from multiple queues associated with access terminals waiting to receive the data. For each access terminal, a weighting factor is calculated based on a temporal fading factor, a throughput fairness factor, and a delay QoS factor. The unit selected for transmission corresponds to the access terminal having the greatest overall weighting factor. The process repeats for each unit being transmitted.Type: ApplicationFiled: November 16, 2001Publication date: May 22, 2003Inventors: Kelvin Kar-Kin Au, Gamini Senarath, Yoon Chae Cheong, Wei Huang
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Publication number: 20030073455Abstract: A method and apparatus are provided for selecting an optimum base station for communicating with a terminal in a wireless communication system. A base station controller stores two candidate sets for each terminal within communication range of the base stations controlled by the base station controller. One candidate set lists base stations for which the channel quality of the uplink channel between the base station and the terminal is acceptable for communication. The other candidate set lists base stations for which the channel quality of the downlink channel between is acceptable for communication. This allows the base station controller to take into account the predominant direction of traffic when assigning base stations for communication with the terminal.Type: ApplicationFiled: October 17, 2001Publication date: April 17, 2003Inventors: Bassam M. Hashem, Shalini S. Periyalwar, Yoon Chae Cheong
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Publication number: 20030012212Abstract: A radio link protocol for a communications system ensures that delivery of Internet protocol data packets occurs within a set delay bound for the packets, in order to satisfy specified quality of service levels. Data packets arriving at a transmitter are subdivided into data blocks. As each block is transmitted, the transmitter starts an associated acknowledgement timer. The timer is turned off, before it expires, if the transmitter timely receives from a receiver a message informing the transmitter that the associated block was successfully received. If such message is not received, the timer expires and the transmitter sends an acknowledgement request signal to the receiver and starts an associated panic timer. The panic timer is turned off, before it expires, if the transmitter subsequently timely receives a message that the associated block was successfully received.Type: ApplicationFiled: March 14, 2001Publication date: January 16, 2003Applicant: Nortel Networks LimitedInventors: Mark Earnshaw, Yoon Chae Cheong, Wei Huang
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Publication number: 20020080820Abstract: A method for sharing transmission of control messages over high data rate networks. Whenever there are data transmitted on the downlink, the control messages are piggybacked. If there is no data transmitted on the downlink, a shared control MAC frame is used. The variable size shared control MAC frame includes same type of control messages for a plurality of fixed terminals. Control information identifiers (CIIDs) are used to indicate the type of the transmitted control messages. The appropriate control information is timely delivered to an identified terminal. Such scalable MAC frame allows for flexibility and an efficient use of high data rate (HDR) transmissions.Type: ApplicationFiled: December 21, 2000Publication date: June 27, 2002Inventors: Bassam M. Hashem, Yoon Chae Cheong, Shalini S. Periyalwar
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Publication number: 20020075841Abstract: A method and apparatus are provided for error correction in a communication system employing Orthogonal Frequency Division Multiplexing. When a remote unit receives an OFDM symbol, a retransmission indicator bit is examined to determine whether the symbol is an original symbol or a retransmitted symbol. If it is a retransmitted symbol and the remote unit has a corresponding symbol stored in memory, then the received symbol is soft-combined with the stored symbol. Each packet in the symbol, either the received symbol if original or the soft-combined symbol if retransmitted, is examined by the remote unit. If the remote unit determines that a particular packet is intended for the remote unit, but can not determine the contents of the payload of the packet, the remote unit sends a retransmission request to the base station for retransmission of the symbol.Type: ApplicationFiled: December 19, 2000Publication date: June 20, 2002Inventors: David G. Steer, Shalini S. Periyalwar, Koon Hoo Teo, Yoon Chae Cheong, Bassam M. Hashem
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Patent number: 5724610Abstract: A selector bank subsystem (SBS) of a code division multiple access (CDMA) system is disclosed, including two portions: a SBSC block and a S/V block. The one SBSC block is designed to manage twelve S/V boards so as to provide 96 traffic channels per SBS self, and thus, one S/V board provides eight communication channels.Type: GrantFiled: June 7, 1995Date of Patent: March 3, 1998Assignee: Hyundai Electronics Industries Co., Ltd.Inventors: Jin Soo Han, Yoon Chae Cheong