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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Patent number: 8116781Abstract: 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: December 20, 2005Date of Patent: February 14, 2012Assignee: Rockstar Bidco LPInventors: Xixian Chen, Xiao-Dong Li, James Weisert, Qiang Yuan, Miroslav Budic
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Publication number: 20120026985Abstract: 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: ApplicationFiled: July 29, 2010Publication date: February 2, 2012Applicant: Telefonaktiebolaget L M Ericsson (publ)Inventors: Hong Ren, Xixian Chen, Xiao-Dong Li, Patrick Lie Chin Cheong
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Publication number: 20120014425Abstract: 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: ApplicationFiled: March 14, 2011Publication date: January 19, 2012Applicant: Telefonaktiebolaget LM Ericsson (publ)Inventors: Jiandong ZHUANG, Xixian CHEN
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Publication number: 20110206007Abstract: A method and system for connection management in a wireless data network, such as a 1×EV-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: ApplicationFiled: May 2, 2011Publication date: August 25, 2011Applicant: NORTEL NETWORKS LIMITEDInventors: Xixian Chen, Weigang Li, Vasanta Chivukula, Shiva Mirzaei-Rezaei, Brian Troup, Miroslav Budic, Yong Zhou, Ryan Santa
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Patent number: 7936720Abstract: 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: April 28, 2006Date of Patent: May 3, 2011Assignee: Nortel Networks LimitedInventors: Xixian Chen, Weigang Li, Vasanta Chivukula, Shiva Mirzaei-Rezaei, Brian Troup, Miroslav Budic, Yong Zhou, Ryan Santa
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Patent number: 7801085Abstract: Methods and apparatus for performing finger de-spreading and MRC combining are provided. A large antenna buffer is used to buffer all the finger signals of the same user so that the receiver can do both de-spreading and MRC at the same time without buffering the de-spreading finger symbols. For each user, a reference time is introduced to align all the finger signals of the same user in the Antenna Buffer. The reference time delay is used to generate the PN codes for de-spreading, as well as to count the number of symbols in a PCG or a frame. Methods for antenna buffer arrangement, interpolating filter implementation, channel estimation and MRC for traffic data channels, timing for the user's finger signal de-spreading and MRC, long code and short code generation for de-spreading, new finger allocation and finger timing adjustment.Type: GrantFiled: June 3, 2003Date of Patent: September 21, 2010Assignee: Ericsson ABInventors: Xixian Chen, Woon Thong, Ganesh Sundararajan, Edward Ken Kiu Mah, Karl Mann
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Patent number: 7760698Abstract: A forward link design is provided employing CDMA (code division multiple access) technologies in which time division multiplexing is employed between data and control information on the forward link to service multiple users per slot. Another forward link design employing CDMA (code division multiple access) technologies is provided in which code division multiplexing between data and control information is employed on the forward link to service multiple users per slot, which is preferably backwards compatible with legacy standards such as IS2000A. A reverse link design is also provided.Type: GrantFiled: October 13, 2006Date of Patent: July 20, 2010Assignee: Alcatel LucentInventors: Xixian Chen, Neil N. McGowan, Muhammad Khaled Islam, Ning Guo, Hong Ren, Litong Li
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Patent number: 7649994Abstract: A method of decoding symbols in which a first codeword has been spread by a second codeword to recover first information and second information is provided. The decoding occurs jointly, with an overall output determining both the first and second information. A first parallel code multiplying operation for each codeword of the second code is followed by a second parallel code multiplying operation for the first code. An overall maximum output of the second parallel code multiplying operations determines the output information.Type: GrantFiled: October 31, 2003Date of Patent: January 19, 2010Assignee: Nortel Networks LimitedInventors: Abdelgader Legnain, Xixian Chen
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Patent number: 7480516Abstract: A cellular wireless communication system includes base transceiver stations and mobile stations that operate with a closed loop power control. The mobile tracking is performed based on the lock in and lock out thresholds by the base transceiver stations. A forward link power control bit is decoded from the reverse channel. An additional threshold is introduced for determining at the base transceiver station whether the decoded forward link power control bit is valid or invalid. The finger energies obtained from a finger processor formed by a RAKE receiver of the base transceiver station are compared to the additional validation threshold. The additional validation threshold is independent of the tracking thresholds and usually greater than them. The validation performance may not be affected by low signal/noise. The forward link traffic channel gain of the base transceiver station is controlled in response to the invalidity of the decoded forward power control bit.Type: GrantFiled: October 28, 2004Date of Patent: January 20, 2009Assignee: Nortel Networks LimitedInventors: Xixian Chen, Guoqiang Xue, Mark Harris, Weigang Li
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Patent number: 7236764Abstract: In code division multiple access communication systems, there are three levels for updating locations of dormant mobile stations (MSs) and setting up fast call. In sector and are levels, the dormant MS send a layer 2 message containing a message type and MS identifier to a base transceiver station (BTS). Since the message is associated with the sector where the MS is located, the network is aware of the MS's location from the updated location. The dormant MS sends to the BTS a reconnect message containing a message type and an MS identifier. The MS's dormant to active state transition is initiated by the MS. In the communication network, sub-packet zone ID is broadcasted in the overhead message. The MS reports its location change on R-CSCH and the network with the BSC level control can page the MS within the zone where the MS sends the report.Type: GrantFiled: January 7, 2004Date of Patent: June 26, 2007Assignee: Nortel Networks LimitedInventors: Hang Zhang, Mo-Han Fong, Ke-Chi Jang, Jun Li, Xixian Chen, Chung-Ching Wang, Geng Wu, James Weisert
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Publication number: 20070076678Abstract: A forward link design is provided employing CDMA (code division multiple access) technologies in which time division multiplexing is employed between data and control information on the forward link to service multiple users per slot. Another forward link design employing CDMA (code division multiple access) technologies is provided in which code division multiplexing between data and control information is employed on the forward link to service multiple users per slot, which is preferably backwards compatible with legacy standards such as IS2000A. A reverse link design is also provided.Type: ApplicationFiled: October 13, 2006Publication date: April 5, 2007Applicant: Nortel Networks LimitedInventors: Xixian Chen, Neil McGowan, Muhammad Islam, Ning Guo, Hong Ren, Litong Li
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Patent number: 7154846Abstract: A forward link design is provided employing CDMA (code division multiple access) technologies in which time division multiplexing is employed between data and control information on the forward link to service multiple users per slot. Another forward link design employing CDMA (code division multiple access) technologies is provided in which code division multiplexing between data and control information is employed on the forward link to service multiple users per slot, which is preferably backwards compatible with legacy standards such as IS2000A. A reverse link design is also provided.Type: GrantFiled: October 24, 2001Date of Patent: December 26, 2006Assignee: Nortel Networks LimitedInventors: Xixian Chen, Neil N. McGowan, Khaled M. Islam, Ning Guo, Hong Ren, Litong Li
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Patent number: 7139575Abstract: Initiation of a hard handoff at a mobile station from an overlay carrier to an underlying carrier in a wireless telecommunications system may be considered based on a first condition being satisfied. Once the first condition is satisfied, hard handoff may be initiated based on at least one of a plurality of further conditions being satisfied. Advantageously, the plurality of further conditions may be arranged to be independent of the total power received at the mobile station and, therefore, independent of loading.Type: GrantFiled: December 27, 2004Date of Patent: November 21, 2006Assignee: Nortel Networks LimitedInventors: Xixian Chen, Neil McGowan, Weigang Li, James R. Weisert, Sabeena Abdulmajeed
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Publication number: 20060245407Abstract: 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: ApplicationFiled: April 28, 2006Publication date: November 2, 2006Applicant: NORTEL NETWORKS LIMITEDInventors: Xixian Chen, Weigang Li, Vasanta Chivukula, Shiva Mirzaei-Rezaei, Brian Troup, Miroslav Budic, Yong Zhou, Ryan Santa
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Publication number: 20060215600Abstract: 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: ApplicationFiled: December 20, 2005Publication date: September 28, 2006Applicant: Nortel Networks LimitedInventors: Xixian Chen, Xiao-Dong Li, James Weisert, Qiang Yuan, Miroslav Budic
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Patent number: 7113538Abstract: Methods, searchers, base stations are provided which search for known codes contained in signals received over wireless channels, from mobile units for example. A coherent correlation is performed between an expected known code, and portions of the received signal during periods which are separated in time. Advantageously, by making the correlation periods separated in time, time diversity is realized such that if one or more of the correlation periods exist while the signal is of poorer quality, for example due to a fade, the remaining correlation periods may still yield a meaningful search statistic. Searching is done during time slots defined with reference to system time, not mobile unit time. Advantageously, this makes the searcher design simpler and more efficient. By performing time diversity searching in this manner, search tasks for one mobile unit(s) can be performed between the search task periods for another mobile unit resulting in a more efficient utilization of searcher resources.Type: GrantFiled: November 1, 2000Date of Patent: September 26, 2006Assignee: Nortel Networks LimitedInventors: Xixian Chen, Runbo Fu, Xin Jin
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Publication number: 20060209674Abstract: A forward link design is provided employing CDMA (code division multiple access) technologies in which time division multiplexing is employed between data and control information on the forward link to service multiple users per slot. Another forward link design employing CDMA (code division multiple access) technologies is provided in which code division multiplexing between data and control information is employed on the forward link to service multiple users per slot, which is preferably backwards compatible with legacy standards such as IS2000A. A reverse link design is also provided.Type: ApplicationFiled: May 1, 2006Publication date: September 21, 2006Inventors: Xixian Chen, Neil McGowan, Muhammad Islam, Ning Guo, Hong Ren, Lltong Li
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Patent number: 6977915Abstract: A method and system for closed loop power control in a wireless communication network. A received signal is despread. The signal power of the despread received signal is estimated. The noise power of the despread received signal is estimated. Estimating the noise power includes multiplying the despread received signal with an orthogonal noise code to cancel the received signal, accumulating the multiplied despread received signal over one frame and determining a signal-to-noise ratio of the received signal at least in part by dividing the estimated signal power by the estimated noise power. A reverse power control bit is determined based on the determined signal-to-noise ratio.Type: GrantFiled: January 30, 2001Date of Patent: December 20, 2005Assignee: Nortel Networks LimitedInventors: Xixian Chen, Neil N. McGowan, Weigang Li, Jeffrey D. Stanier, M. Khaled Islam, Qiang Shen, Xin Jin
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Publication number: 20040179492Abstract: In code division multiple access communication systems, there are three levels for updating locations of dormant mobile stations (MSs) and setting up fast call. In sector and are levels, the dormant MS send a layer 2 message containing a message type and MS identifier to a base transceiver station (BTS). Since the message is associated with the sector where the MS is located, the network is aware of the MS's location from the updated location. The dormant MS sends to the BTS a reconnect message containing a message type and an MS identifier. The MS's dormant to active state transition is initiated by the MS. In the communication network, sub-packet zone ID is broadcasted in the overhead message. The MS reports its location change on R-CSCH and the network with the BSC level control can page the MS within the zone where the MS sends the report.Type: ApplicationFiled: January 7, 2004Publication date: September 16, 2004Inventors: Hang Zhang, Mo-Han Fong, Ke-Chi Jang, Jun Li, Xixian Chen, Chung-Ching Wang, Geng Wu, James Weisert
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Patent number: 6704300Abstract: The invention is directed to a method and system for acquisition of a time stamped signal burst while preserving timing information. A system for acquisition of a time stamped signal burst while preserving timing information. The system includes a first framer, an offset frequency compensator and a second framer. The first framer is for framing a buffered signal burst using least mean squares tuning to produce a first time stamp. The offset frequency compensator is for substantially removing a frequency offset from the first time stamp to produce a rough signal burst. The second framer is for framing the rough signal burst using least mean squares tuning to produce a fine signal burst arid a second time stamp, the second time stamp being more reliable than the first time stamp. A method system or acquisition of a time stamped signal burst while preserving timing information including the steps of framing using LMS and compensating for frequency offset.Type: GrantFiled: August 16, 1999Date of Patent: March 9, 2004Assignee: Nortel Networks LimitedInventors: Xixian Chen, Song Zhang, Shiquan Wu