Patents by Inventor Xixian Chen
Xixian Chen 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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Publication number: 20150124709Abstract: Methods and apparatus are disclosed for a generalized outer loop link adaptation procedure. A normal outer-loop control procedure corrects an estimated SINR, which may be inaccurate if the estimate SINR is mapped from a channel quality estimate that does not reflect the true radio link condition. A normal outer control procedure functions properly only when a normal Modulation and Coding Scheme (MCS) is selected. A normal MCS is the highest Modulation and Coding Scheme (MCS) with which the target Block Error Rate (BLER) can be achieved given a certain number of HARQ (Hybrid Automatic Repeat Request) transmissions. The present application discloses a generalized outer loop link adaptation procedure that functions properly whether the selected MCS is normal, aggressive, or conservative.Type: ApplicationFiled: November 5, 2013Publication date: May 7, 2015Applicant: Telefonaktiebolaget L M EricssonInventors: Hong Ren, Xixian Chen, Peter Hazy
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Publication number: 20150117321Abstract: A method and base station for adjusting outer-loop adjustment values used for link adaptation in a wireless communication network is provided. A modulation of a user equipment is determined and a success or failure of a Transport Block (TB) based on a TB feedback message is determined. Based on the TB feedback, one of an acknowledgement counter and a non-acknowledgement counter is incremented corresponding to the determined modulation. An upward step size for the determined modulation is updated based on the respective acknowledgement counter and the non-acknowledgement counter to affect link adaption.Type: ApplicationFiled: October 30, 2013Publication date: April 30, 2015Inventors: Xixian CHEN, Hong REN, Edward MAH, Shiguang GUO, Ping YU, Guoqiang LU
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Patent number: 9014135Abstract: Methods of performing link adaptation in a wireless communication system for simultaneous transmission of codewords include selecting initial modulation and coding scheme (MCS) levels for the codewords, estimating a size ratio of the codewords, determining a number of scheduling blocks (SB) for the codewords with the initial MCS levels, and determining revised MCS levels for the codewords in response to the determined number of SBs. Transport block sizes are computed for the codewords, and it is determined if there is a need to increase the number of scheduling blocks in at least one of the codewords. If there is a need to increase the number of scheduling blocks in a codeword, scheduling blocks are added to the codeword, and the transport block size for the codeword is recomputed. The codewords are then simultaneously transmitted over different multiple input-multiple output (MIMO) communication channels using the same time and frequency resources.Type: GrantFiled: January 3, 2012Date of Patent: April 21, 2015Assignee: Telefonaktiebolaget L M Ericsson (publ)Inventors: Ping Yu, Girum Alebachew Fantaye, Xixian Chen, Hong Ren
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Patent number: 8995259Abstract: Systems and methods provide for performing admission control in a communications network. The method includes: receiving a request for an entity or service for admission to the communications network; calculating resources, wherein the step of calculating resources includes: estimating a first future resource use for current entities and services in the communications network; and estimating a second future resource use for the entity or service received in the request; determining admission to the communications network of the received request based at least in part on the step of calculating resources; and using a partitionable booking window, if admission is allowed for the received request, for booking the first and second future resource uses based at least in part on the step of calculating resources.Type: GrantFiled: June 19, 2012Date of Patent: March 31, 2015Assignee: Telefonaktiebolaget L M Ericsson (publ)Inventors: Ricardo Paredes, Xixian Chen, Anders Ohlsson
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Publication number: 20150045040Abstract: Methods and apparatus are disclosed for handing over of a high-speed mobile terminal or user equipment from a source network node to a target network node. Reliable methods for measuring the speed of a moving user equipment are disclosed. Parameters used in a handover procedure are also adjusted in accordance with the speed of the user equipment. For handing over a high-speed user equipment, the present application discloses that the source network node can coordinate with the target network node and other candidate network nodes in transmitting a handover command to prevent handover failures.Type: ApplicationFiled: August 12, 2013Publication date: February 12, 2015Applicant: Telefonaktiebolaget L M Ericsson (Publ)Inventors: Xiaoming Lai, Xixian Chen, Weigang Li
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Patent number: 8897124Abstract: A wireless terminal adapted to function in a code division multiple access (CDMA) communications system is provided. The terminal includes a receiver adapted to receive frames having a slot structure in which there is a user identification channel and a shared channel, the shared channel having been transmitted using a plurality of Walsh codes, and containing content for either a plurality of voice users, a plurality of voice users and one high-rate data user, or only one high-rate data user. A slot of the shared channel contains content for a plurality of users which was transmitted in parallel using different Walsh code spaces for different users. The wireless terminal is adapted to decode the user identification channel to determine when a slot of the shared channel contains voice and/or high-rate data content for the wireless terminal.Type: GrantFiled: June 28, 2012Date of Patent: November 25, 2014Assignee: Alcatel LucentInventors: Xixian Chen, Neil N. McGowan, Muhammad Khaledul Islam, Ning Guo, Hong Ren, Litong Li
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Patent number: 8842565Abstract: A method and apparatus is provided for assigning resources for an acknowledgement channel, such as the PHICH in LTE systems. A list of acknowledgement channels for a group of scheduled mobile terminals is generated. The list is sorted in descended order of the required transmit energies for the corresponding mobile terminals. The acknowledgement channels are then assigned to channel groups one at a time in sorted order to an available channel group with the lowest cumulative transmit energy. By sorting the channel list before assigning resources, the variance in the transmit energies for different channel groups is reduced. Given enough number of acknowledgement channel groups, the small variance in the transmit energies for different channel groups implies improved error rate performance.Type: GrantFiled: December 31, 2010Date of Patent: September 23, 2014Assignee: Telefonaktiebolaget L M Ericsson (Publ)Inventors: Hong Ren, Xixian Chen
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Publication number: 20140243006Abstract: Various embodiments provide for the management of wireless resources, which can reduce call blocking by allowing high priority services, under suitable conditions, to use resources allocated to low priority services. Thus high priority services can pre-empt the usage of wireless resources by low priority services. This has the advantage of reducing call blocking for high priority calls, while permitting low priority calls to have more access to radio resources than conventional systems with the same call blocking rate. Thus a base station can implement a preemption mechanism that would reclaim Walsh Code and Forward Power resources from an active Supplemental Channel (SCH) burst in order to accommodate incoming Fundamental Channel (FCH) requests.Type: ApplicationFiled: April 30, 2014Publication date: August 28, 2014Inventors: Xixian Chen, Xiao-Dong Li, James Weisert, Qiang Yuan, Miroslav Budic
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Patent number: 8804671Abstract: A radio user equipment (UE) mobility status is determined in a communications node. UE mobility status measurements associated with the UE communicating over a radio channel are performed. The UE mobility status corresponds to a degree of variation of the radio channel over time. Channel characteristics of the radio channel at a first time and at a second later time are determined. Based on the determined channel characteristics, a channel characteristic error metric is determined and compared to a predetermined threshold. The UE mobility status is determined based on one or more iterations of the threshold comparison.Type: GrantFiled: March 14, 2011Date of Patent: August 12, 2014Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Jiandong Zhuang, Xixian Chen
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Patent number: 8787340Abstract: A method of connection setup in mobile wireless data communications systems is disclosed where the connection setup time is decreased for delay-sensitive communications sessions relative to the normal connection setup time for confidence-dependent communications sessions. This is achieved by performing some of the connection set-up steps for delay-sensitive communications sessions after successfully demodulating a smaller number of indications identifying an access terminal's desired serving resource than would be demodulated in the case of a confidence-dependent communication session prior to performing the same connection set-up steps.Type: GrantFiled: February 2, 2012Date of Patent: July 22, 2014Assignee: Ericsson ABInventors: Xixian Chen, Vasanta Chivukula, Weigang Li, Guoqiang Xue, Ryan Santa, Miroslav Budic, Brian Troup, Martin Kendall
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Patent number: 8761108Abstract: A radio resource management method is provided. Data for transmission is stored. The stored data is associated with user equipment (UE). A channel quality is estimated. A first modulation and coding scheme (MCS) is determined based at least in part on the estimated channel quality. A first number of scheduling blocks (SBs) required to transmit the stored data is determined based at least in part on the first MCS. The first number of SBs are a minimum of an initial number of SBs and available amount of SBs. A link quality is calculated based at least in part on a channel condition associated with the first number of SBs. A second MCS is determined based at least in part on the calculated link quality and a link quality requirement.Type: GrantFiled: June 25, 2012Date of Patent: June 24, 2014Assignee: Telefonaktiebolaget L M Ericsson (publ)Inventors: Hong Ren, Girum Alebachew Fantaye, Xixian Chen, Ping Yu
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Patent number: 8750891Abstract: The invention provides for the management of wireless resources, which can reduce call blocking by allowing high priority services, under suitable conditions, to use resources allocated to low priority services. Thus high priority services can pre-empt the usage of wireless resources by low priority services. This has the advantage of reducing call blocking for high priority calls, while permitting low priority calls to have more access to radio resources than conventional systems with the same call blocking rate. Thus a base station can implement a preemption mechanism that would reclaim Walsh Code and Forward Power resources from an active Supplemental Channel (SCH) burst in order to accommodate incoming Fundamental Channel (FCH) requests.Type: GrantFiled: January 20, 2012Date of Patent: June 10, 2014Assignee: Microsoft CorporationInventors: Xixian Chen, Xiao-Dong Li, James Weisert, Qiang Yuan, Miroslav Budic
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Publication number: 20140133317Abstract: A node (28) of a radio access network (20) communicates over a radio interface (32) with a wireless terminal (30). The node (28) comprises a transmitter (34) and a controller (40). The transmitter (34) selectively operates in plural multiple input multiple output (MIMO) modes for downlink transmission over the radio interface (32). The controller (40) uses both a terminal speed value and a throughput value to make a determination when to switch between the plural multiple input multiple output (MIMO) modes for communicating with the wireless terminal. The plural MIMO modes comprise a first mode and a second mode. In the first mode open loop MIMO operates with cyclical diversity delay. In the second mode open loop MIMO operates without cyclical diversity delay. Although operating in open loop MIMO, advantages such as those of closed loop MIMO are realized.Type: ApplicationFiled: November 9, 2012Publication date: May 15, 2014Applicant: Telefonaktiebolaget L M Ericsson (Publ)Inventors: Xixian Chen, Peter Deane, Xiaoming Lai
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Patent number: 8699415Abstract: A method and system for connection management in a wireless data network, such as a 1xEV-DO network adds connections to new network sectors upon receipt of a connection request from an active terminal, but removes data connections that the active terminal requests to be dropped only after confirmation from the active terminal that a channel allocation message has been received and applied. The active network maintains an active set of connections that is at least as large as the active set maintained by the active terminal and does not initiate a connection termination if no confirmation of the channel allocation message is received. This allows for a reduction in the number of dropped connections.Type: GrantFiled: May 2, 2011Date of Patent: April 15, 2014Assignee: Apple Inc.Inventors: Xixian Chen, Weigang Li, Vasanta Chivukula, Shiva Mirzaei-Rezaei, Brian Troup, Miroslav Budic, Yong Zhou, Ryan Santa
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Publication number: 20130343290Abstract: A radio resource management method is provided. Data for transmission is stored. The stored data is associated with user equipment (UE). A channel quality is estimated. A first modulation and coding scheme (MCS) is determined based at least in part on the estimated channel quality. A first number of scheduling blocks (SBs) required to transmit the stored data is determined based at least in part on the first MCS. The first number of SBs are a minimum of an initial number of SBs and available amount of SBs. A link quality is calculated based at least in part on a channel condition associated with the first number of SBs. A second MCS is determined based at least in part on the calculated link quality and a link quality requirement.Type: ApplicationFiled: June 25, 2012Publication date: December 26, 2013Applicant: TELEFONAKTIEBOLAGET L M ERICSSON (PUBL)Inventors: Hong REN, Girum Alebachew FANTAYE, Xixian CHEN, Ping YU
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Publication number: 20130170469Abstract: Methods of performing link adaptation in a wireless communication system for simultaneous transmission of codewords include selecting initial modulation and coding scheme (MCS) levels for the codewords, estimating a size ratio of the codewords, determining a number of scheduling blocks (SB) for the codewords with the initial MCS levels, and determining revised MCS levels for the codewords in response to the determined number of SBs. Transport block sizes are computed for the codewords, and it is determined if there is a need to increase the number of scheduling blocks in at least one of the codewords. If there is a need to increase the number of scheduling blocks in a codeword, scheduling blocks are added to the codeword, and the transport block size for the codeword is recomputed. The codewords are then simultaneously transmitted over different multiple input-multiple output (MIMO) communication channels using the same time and frequency resources.Type: ApplicationFiled: January 3, 2012Publication date: July 4, 2013Applicant: Telefonaktiebolaget L M Ericsson (publ)Inventors: Ping Yu, Girum Alebachew Fantaye, Xixian Chen, Hong Ren
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Publication number: 20130155852Abstract: Systems and methods provide for performing admission control in a communications network. The method includes: receiving a request for an entity or service for admission to the communications network; calculating resources, wherein the step of calculating resources includes: estimating a first future resource use for current entities and services in the communications network; and estimating a second future resource use for the entity or service received in the request; determining admission to the communications network of the received request based at least in part on the step of calculating resources; and using a partitionable booking window, if admission is allowed for the received request, for booking the first and second future resource uses based at least in part on the step of calculating resources.Type: ApplicationFiled: June 19, 2012Publication date: June 20, 2013Applicant: TELEFONAKTIEBOLAGET L M ERICSSON (PUBL)Inventors: Ricardo PAREDES, Xixian CHEN, Anders OHLSSON
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Patent number: 8457002Abstract: The present invention provides a method and apparatus for improving wireless communication network performance and efficiency, based on detecting the occurrence of grant loss in relation to the transmission of scheduling grants to mobile terminals over a downlink control channel. Grant loss detection is based on detecting erasure events corresponding to the transmitted scheduling grants, and the incidence of grant loss with respect to a given mobile terminal can be tracked and used to compensate the control value(s) used for link adaptation of the downlink control channel, with respect to that terminal. Additionally, or alternatively, when a given grant is determined to be lost, a new grant is sent and the HARQ redundancy version is reset for the newly scheduled transmission.Type: GrantFiled: July 29, 2010Date of Patent: June 4, 2013Assignee: Telefonaktiebolaget LM Ericsson (publ)Inventors: Hong Ren, Xixian Chen, Xiao-Dong Li, Patrick Lie Chin Cheong
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Publication number: 20130028307Abstract: In a method of adjusting a modulation and coding scheme (MCS) level for a transmission on a communication channel between a base station and a mobile terminal, at the base station: a target value for an error metric is defined; the error metric is measured; an MCS offset based on a degree of deviation of the measurement of the error metric from the target value is determined; an indication of a channel quality measurement for the communication channel is received from the mobile terminal; a pre-adjusted MCS level corresponding to the indication of the channel quality measurement is determined using a fixed mapping between a set of channel quality levels and a corresponding set of MCS levels; an adjusted MCS level is determined by adding the MCS offset to the pre-adjusted MCS level; and the adjusted MCS level is assigned to the transmission.Type: ApplicationFiled: September 14, 2012Publication date: January 31, 2013Applicant: RESEARCH IN MOTION LIMITEDInventors: Hong Ren, Xixian Chen, Ping Yu, Mircea Dumitrescu
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Publication number: 20130010907Abstract: A wireless receiver receives reference signals over a wireless link The wireless receiver calculates a selection indication based on the received reference signals, and the wireless receiver selects from among plural channel estimation techniques based on the selection indication, where the selected channel estimation technique is usable to perform channel estimation of the wireless link.Type: ApplicationFiled: September 15, 2012Publication date: January 10, 2013Applicant: Research In Motion LimitedInventors: Jiandong Zhuang, Xixian Chen, Edward Ken Kiu Mah