Patents by Inventor Zhifeng Tao

Zhifeng Tao 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).

  • Publication number: 20100081441
    Abstract: A method allocates bandwidth from a radio frequency spectrum in a cellular network including a set of cells. Each cell includes a base station for serving a set of mobile stations in the cell. An area around each base station is partitioned into a center region and a boundary region. In each base station, bandwidth for use in the center region is reserved according to an inter-cell interference coordination (ICIC) protocol, and bandwidth for use in the boundary region is reserved according to the ICIC protocol and a base station cooperation (BSC) protocol. Then, the bandwidth is allocated to mobile stations as the mobile stations communicate with the base station in the center regions and the boundary regions according to the bandwidth reservations.
    Type: Application
    Filed: September 30, 2008
    Publication date: April 1, 2010
    Inventors: Zhifeng Tao, Koon Hoo Teo, Yu-Jung Chang, Xuehong Mao
  • Publication number: 20100061469
    Abstract: A method allocates frequency subchannels in an orthogonal frequency-division multiple access (OFDMA) network including a set of base stations and a set of mobile stations for each base station. A graph of nodes and edges is constructed, in which the nodes represent the mobile stations in the network, and the edges connecting the nodes represent subchannel allocation constraints to be satisfied for the mobile stations represented by the nodes. The nodes are colored with colors selected from a set of colors such that subchannel allocation constraints of a pair of nodes connected by one of the edges are satisfied. The subchannels are allocated to the mobile stations according to the colors of the corresponding the nodes.
    Type: Application
    Filed: September 5, 2008
    Publication date: March 11, 2010
    Inventors: Zhifeng Tao, Yu-Jung Chang, Jinyun Zhang
  • Publication number: 20100034128
    Abstract: A method for signaling in a wireless network, including a base station (BS) in a cell, wherein the network operates according to the IEEE 802.16 standard, exchanges messages between a subscriber station (SS), when the SS enters the cell. The messages indicate whether the SS and the BS are enabled to use an Upper Layer Signaling (R2) and a Dynamic Service Addition/Change (DSA/DSC) signaling (DSx) for multi-cast broadcast services (MBS) for subsequent message exchanged between the SS and the BS, after the SS is admitted into the cell.
    Type: Application
    Filed: March 6, 2009
    Publication date: February 11, 2010
    Inventors: Raymond Yim, Zhifeng Tao, Toshiyuki Kuze
  • Patent number: 7630355
    Abstract: A method and system enables and improves performance of hybrid automatic repeat request (HARQ) operations on channels between stations of an orthogonal frequency division multiple access (OFDMA) wireless communication network. There, the number of parallel HARQ channels is increased adaptively, and one connection identifier is used to unambiguously identify a set of MAC protocol data units (MPDUs) communicated over parallel HARQ channels. A sequence number is used to avoid out-of-order MPDU delivery when MPDUs are transmitted over parallel HARQ channels. The MPDUs can be concatenated or encapsulated. The maximum number of the parallel HARQ channels can be increased to 256, and can be negotiated when a station enters or re-enters the network.
    Type: Grant
    Filed: January 5, 2007
    Date of Patent: December 8, 2009
    Assignee: Mitsubishi Electric Research Laboratories, Inc.
    Inventors: Zhifeng Tao, Toshiyuki Kuze, Shigeru Uchida, Kentarou Sawa, Koon Hoo Teo, Jinyun Zhang
  • Publication number: 20090262852
    Abstract: A method transmits a sequence of symbols in a multiple-input multiple-output (MIMO) network including a transmitter having a set of transmit antennas and a receiver having a set of receive antennas. The sequence of symbols is represented by a vector S=[S1 S2 S3 S4]T of individual symbols, where T is a transpose operator. The individual symbols are transmitted as a transmit matrix S = [ S 1 - S 2 * S 1 - S 2 * S 2 S 1 * S 2 S 1 * S 3 - S 4 * - S 3 S 4 * S 4 S 3 * - S 4 - S 3 * ] , where * is a complex conjugate, and wherein each column of the matrix S represents the symbols transmitted at each transmission interval, and subscripts index the set of transmit antennas.
    Type: Application
    Filed: September 17, 2008
    Publication date: October 22, 2009
    Inventors: Philip V. Orlik, Wataru Matsumoto, Andreas F. Molisch, Zhifeng Tao, Jinyun Zhang
  • Publication number: 20090245086
    Abstract: A method allocates radio channel resource in an orthogonal frequency-division multiple access network including a set of base stations (BS) and a set of mobile stations (MS). For each BS, a diversity set is maintained for the sets of MS. Each BS determines possible interference at the MS based on the diversity set. A graph is constructed, in which nodes represent the sets of MS, and each edge between a pair of nodes represents channel interference between the MS represented by the pair of nodes. A weight is assigned to each edge, which reflects interference and signal strength on the subchannel between the two MSs connected by the edge. Channel resources are allocated to the MS based on the graph.
    Type: Application
    Filed: April 30, 2008
    Publication date: October 1, 2009
    Inventors: Zhifeng Tao, Yu-Jung Chang, Jinyun Zhang
  • Publication number: 20090245085
    Abstract: A method allocates radio channel resources in an orthogonal frequency-division multiple access network including a set of base stations (BS) and a set of mobile stations (MS). For each BS, a diversity set is maintained for the sets of MS. Each BS determines possible interference at the MS based on the diversity set. A graph is constructed, in which nodes represent the sets of MS, mid each edge between a pair of nodes represents channel interference between the MS represented by the pair of nodes. A weight is assigned to each edge, which reflects interference between the two MSs connected by the edge. The interference graph is partitioned into non-overlapping clusters of nodes based on a structure of the interference graph, the potential interference, so that a sum of the weights of the edges between each cluster is maximized. Based upon the graph partitioning, the channel resources are allocated to the mobile stations in order to maximize the system capacity.
    Type: Application
    Filed: April 30, 2008
    Publication date: October 1, 2009
    Inventors: Zhifeng Tao, Yu-Jung Chang, Jinyun Zhang
  • Patent number: 7593342
    Abstract: A method selects a route in a wireless cooperative relay network of nodes, the nodes including a source, a set of relays, and a destination. A codeword is encoded as a data stream. The data stream is transmitted from a source to a destination via a set of relays. Mutual information is accumulated at a particular node to decode the data stream and recover the codeword. Then, a route from the source to the destination is selected based on channel state information between the nodes while transmitting and accumulating.
    Type: Grant
    Filed: December 5, 2006
    Date of Patent: September 22, 2009
    Assignee: Mitsubishi Electric Research Laboraties, Inc.
    Inventors: Andreas F. Molisch, Neelesh B. Mehta, Jonathan S. Yedidia, Zhifeng Tao, Zafer Sahinoglu, Philip V. Orlik, Jin Zhang
  • Publication number: 20090225720
    Abstract: A method estimates channels in a wireless cooperative cellular network including a set of base stations, and each base station communicates cooperatively with a set of mobile stations. A first sounding signal including a first midamble is transmitted from a first base station to a first mobile station. A second sounding signal including a second midamble is transmitted simultaneously from a second base station to the first mobile station, wherein the first and second midamble are disjoint in time, and wherein the first and second midambles are used to estimate the channels between the first base station and the first mobile station, and the second base station and the first mobile station, respectively.
    Type: Application
    Filed: January 23, 2009
    Publication date: September 10, 2009
    Inventors: Andreas F. Molisch, Zhifeng Tao, Philip V. Orlik, Jinyun Zhang, Lun Dong, Lingjia Liu, Toshiyuki Kuze
  • Publication number: 20090225728
    Abstract: An orthogonal frequency division multiple access (OFDMA) network including a base station (BS) associated with a set of mobile stations (MS) in a cell. The set of MS are grouped into sets of active MS, wherein each set of active MS corresponds to a beam formed at the BS. The BS transmits a down link (DL) subframe using analog beam forming (ABF), wherein the DL subframe has one ABF zone for each set of active MS and each corresponding beam.
    Type: Application
    Filed: January 23, 2009
    Publication date: September 10, 2009
    Inventors: Zhifeng Tao, Andreas F. Molisch, Philip V. Orlik, Jinyun Zhang, Toshiyuki Kuze
  • Publication number: 20090225883
    Abstract: A base station transmits a set of sounding requests to a set of mobile station (MS) in a cell, using a set of beams, wherein there is one beam for each sounding request. Qualities of sounding signals transmitted by the set of MSs in response to receiving the sounding request are measured, and the set of MSs are grouping into subsets according to the qualities, wherein there is one subset of MSs associated with each beam.
    Type: Application
    Filed: March 12, 2009
    Publication date: September 10, 2009
    Inventors: Philip V. Orlik, Toshiyuki Kuze, Andreas F. Molisch, Zhifeng Tao, Jinyun Zhang
  • Publication number: 20090220085
    Abstract: Provided is a data structure for transmitting a relay media access control (MAC) protocol data unit (PDU) between stations in a multi-hop relay network. The MAC PDU includes an encryption control bit, an allocation subheader bit, a grant management subheader bit, a fragmentation subheader bit, a packing subheader bit, a quality of service subheader bit, and an encryption key sequence. The relay MAC PDU is transmitted in a tunnel established between base station and relay station.
    Type: Application
    Filed: September 4, 2008
    Publication date: September 3, 2009
    Inventors: Zhifeng Tao, Jinyun Zhang
  • Publication number: 20090213778
    Abstract: A hop-by-hop and multi-hop approach for fragmentation and packing are provided for a wireless multi-hop relay network. The fragmentation and packing operate at ingress, intermediate, and egress stations of a tunnel connecting a base station (BS) with an access relay station (RS). A format of the associated relay fragmentation and packing subheader are specified. In addition, a tunnel data includes numbered blocks to ensure correct packet sequencing for proper packet construction and reassembly for fragmentation and packing in the multi-hop relay network.
    Type: Application
    Filed: September 3, 2008
    Publication date: August 27, 2009
    Inventors: Zhifeng Tao, Jinyun Zhang
  • Publication number: 20090201867
    Abstract: A method allocates bandwidth from a radio frequency spectrum in a cellular network including a set of cells. Each cell includes a base station for serving a set of mobile stations in the cell. An area around each base station is partitioned into a center region and an edge region. In each base station, cell-center bandwidth for use by the mobile stations in the center region is reserved according to an inter-cell interference coordination (ICIC) protocol, and cell-edge bandwidth for use by the mobile stations in the edge region is reserved according to the ICIC protocol. The bandwidth can be fixed or adaptive to reduce the signaling overhead. The adaptive bandwidth can be further partitioned into reserved and the free bands. Mobile stations are classified as primary and secondary users, depending on whether they use or are assigned the fixed or adaptive band radio resources.
    Type: Application
    Filed: December 15, 2008
    Publication date: August 13, 2009
    Inventors: Koon Hoo Teo, Zhifeng Tao, Xuehong Mao, Amine Maaref
  • Publication number: 20090180568
    Abstract: A method transmits a block of symbols in a multiple-input multiple-output (MIMO) network including a transmitter having a set of transmit antennas and a receiver having a set of receive antennas. A block of symbols is coded with a first code to generate a first block, which is transmitted and received. If a decoding of the first block is incorrect, then block of symbols is coded with the first code and then a second code different than the first code to generate a second block. The second block is transmitted, received and combined with the first block to recover the block of symbols.
    Type: Application
    Filed: September 26, 2008
    Publication date: July 16, 2009
    Inventors: Philip V. Orlik, Wataru Matsumoto, Andreas F. Molisch, Zhifeng Tao, Jinyun Zhang
  • Publication number: 20090180459
    Abstract: A method communicates symbols in a cell of a multiple-input multiple-output (MIMO) network that includes a set of mobile station and a base station. The symbols are communicated using orthogonal frequency division multiplexing (OFDM) and time division duplex (TDM). A frame for communicating the symbols between the base station and the mobile station is constructed. The frame is partitioned into a downlink subframe and an uplink subframe. The uplink subframe is partitioned into a first zone and a second zone, wherein the first zone uses orthogonal frequency division multiple access (OFDMA) and the second zone uses single carrier frequency division multiple access (SC-FDMA).
    Type: Application
    Filed: September 29, 2008
    Publication date: July 16, 2009
    Inventors: Philip V. Orlik, Andreas F. Molisch, Zhifeng Tao, Jinyun Zhang
  • Publication number: 20090122777
    Abstract: A method and a system for selecting antennas in an orthogonal frequency division multiple access (OFDMA) network. The network includes a base station and mobile stations. The mobile station includes multiple antennas. The base station and the mobile stations communicate with each other using frames. The base station transmits a down-link (DL) subframe of the frame to the mobile station. The DL subframe allocates one or more symbols and one or more subcarriers of an up-link (UL) subframe of the frame for antenna selection signals. The mobile station transmits the UL subframe including the antenna selection signals at the allocated subcarriers and symbols to the base station. Then, the base station selects a subset of the antennas based on the antenna selection signals.
    Type: Application
    Filed: November 9, 2007
    Publication date: May 14, 2009
    Inventors: Zhifeng Tao, Jinyun Zhang
  • Publication number: 20090124290
    Abstract: A method for selects antennas in a spatial division multiple access (SDMA) wireless network that includes a base station and a set of mobile stations, in which the set of mobile stations includes one or more designated mobile stations, and in which each designated mobile station has a set of multiple antennas. Channel state information (CSI) is acquired for a channel between each mobile station in the set of mobile stations and the base station, and in which the CSI for each designated mobile station is acquired for different subsets of the set of multiple antennas at each designated mobile station. For each designated mobile station, a globally optimal subset of the set of antennas is selected based on the CSI acquired from all the mobile stations.
    Type: Application
    Filed: November 9, 2007
    Publication date: May 14, 2009
    Inventors: Zhifeng Tao, Tairan Wang, Andreas F. Molisch, Philip V. Orlik, Jinyun Zhang
  • Publication number: 20090111473
    Abstract: A method and system communicates cooperatively between base stations and mobile stations in a wireless cellular network. At least two mobile stations are detected in a handover region. A diversity set is established for each mobile station in the handover region. Each diversity set identifies at least two base stations that can communicate with the associated mobile station. The at least two base stations and the at least two mobile stations are combined into members of a cooperation set. A resource is allocated to selected members of the cooperative set. The selected members are notified of the allocated resource. Then, the selected base stations of the cooperation set communicate concurrently with the selected mobile stations using the same allocated resource.
    Type: Application
    Filed: October 31, 2007
    Publication date: April 30, 2009
    Inventors: Zhifeng Tao, Tairan Wang, Jinyun Zhang
  • Publication number: 20090074088
    Abstract: A method performs a hybrid automatic repeat-request (HARQ) operation in a wireless orthogonal frequency division multiple access (OFDMA) network. A quality of a channel between a transmitter and a receiver is estimated as an error metric. A packet for the HARQ operation is fragmented adaptively at the transmitter according to the estimated error metric. The fragmentation is performed at the HARQ layer when the error metric is less than a predetermined threshold, otherwise the fragmentation is performed at the MAC layer.
    Type: Application
    Filed: September 13, 2007
    Publication date: March 19, 2009
    Inventors: Zhifeng Tao, Anfei Li, Koon Hoo Teo, Jinyun Zhang