Patents by Inventor Anastasios Stamoulis

Anastasios Stamoulis 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: 20070105574
    Abstract: Systems and methods are described that facilitate evaluating conditions of nodes (e.g., access points, access terminals, etc.) in a wireless communication environment to determine a level of disadvantage for a given node relative to other nodes. A first node may receive a resource utilization message (RxRUM) and may determine a level of disadvantage for a node that sent the RxRUM. The first node may then compare its own level of disadvantage to the sending node in order to permit a determination of an appropriate course of action in response to the RxRUM.
    Type: Application
    Filed: October 26, 2006
    Publication date: May 10, 2007
    Applicant: QUALCOMM Incorporated
    Inventors: Rajarshi Gupta, Ashwin Sampath, David Julian, Gavin Horn, Anastasios Stamoulis, Nikhil Jain, Husheng Li, Rajat Prakash
  • Publication number: 20070105575
    Abstract: Systems and methods are disclosed that facilitate wireless communication using resource utilization messages (RUMs), in accordance with various aspects. A RUM may be generated for a first node, such as an access point or an access terminal, to indicate that a first predetermined threshold has been met or exceeded. The RUM may be weighted to indicate a degree to which a second predetermined threshold has been exceeded. The first and/or second predetermined thresholds may be associated with various parameters associated with the node, such as latency, throughput, data rate, spectral efficiency, carrier-to-interference ratio, interference-over-thermal level, etc. The RUM may then be transmitted to one or more other nodes to indicate a level of disadvantage experienced by the first node.
    Type: Application
    Filed: October 26, 2006
    Publication date: May 10, 2007
    Applicant: QUALCOMM Incorporated
    Inventors: Ashwin Sampath, Rajarshi Gupta, David Julian, Gavin Horn, Anastasios Stamoulis, Nikhil Jain, Husheng Li, Rajat Prakash
  • Publication number: 20070105573
    Abstract: Systems and methods are disclosed that facilitate dynamically adjusting a number of resources, such as channels, frequencies, tones, etc., occupied by a node (e.g., an access point, and access terminal, etc.) in accordance with various aspects. A level of service experienced at the node may be determined, and a resource utilization message (RUM) may be generated if the level of service is at or below a predetermined threshold level (e.g., an acceptable level of service). The RUM may indicate a number of resources selected by the node for subsequent use, and may be transmitted to one or more other nodes.
    Type: Application
    Filed: October 26, 2006
    Publication date: May 10, 2007
    Applicant: QUALCOMM Incorporated
    Inventors: Rajarshi Gupta, Ashwin Sampath, Gavin Horn, Anastasios Stamoulis, Nikhil Jain
  • Publication number: 20070105576
    Abstract: Systems and methods are described that facilitate data communication in a wireless communication environment. According to various aspects, a node, such as an access point or an access terminal, may determine a number of channels over which it will transmit a communication signal. The node may then select channels based on whether the channels are available or unavailable, wherein available channels are preferentially selected over unavailable channels. The node may then transmit a signal over the at least one of the selected channels.
    Type: Application
    Filed: October 26, 2006
    Publication date: May 10, 2007
    Applicant: QUALCOMM Incorporated
    Inventors: Rajarshi Gupta, Rajat Prakash, Ashwin Sampath, David Julian, Gavin Horn, Nikhil Jain, Anastasios Stamoulis
  • Publication number: 20070070936
    Abstract: A mobile communications device is described that includes a processor configured to establish a network connection with a server in a network and a data generator under the control of the processor that is configured to periodically generate a data unit at a rate having a fixed period. The mobile communications device also includes a transceiver configfured to transmit, via the network connection, the data unit during one of the plurality of slots, each slot being an adjacent fractional portion of the fixed period.
    Type: Application
    Filed: September 28, 2005
    Publication date: March 29, 2007
    Inventors: Anastasios Stamoulis, Nikhil Jain
  • Patent number: 7173975
    Abstract: In an environment where a block transmission takes place via a frequency selective channel that is characterized by channel parameters that change with time in the course of the transmission of a block, an arrangement employs pilot signals to ascertain some of the parameters, and estimates the remaining parameters through an interpolation process. In some embodiments, channel coefficients estimates are improved by employing estimates from previous blocks. In an OFDM system, the pilot signals are advantageously selected to be in clusters that are equally spaced from each other in the time or the frequency domains. This approach applies to multiple antennae arrangements, as well as to single antenna arrangements, and to arrangements that do, or do not, use space-time coding.
    Type: Grant
    Filed: May 21, 2002
    Date of Patent: February 6, 2007
    Inventors: Naofal Al-Dhahir, Suhas N. Diggavi, Anastasios Stamoulis
  • Patent number: 7130355
    Abstract: In an environment where the transmission medium leading to the receiver is time-variant within a block of received signals, and where transmission medium has an finite impulse response extending over a number of symbols intervals, a receiver that includes a filter that, based on an estimate of the transmission channel, is controlled to have filter coefficients that minimize inter-carrier interference due to the intra-block time variations in the transmission medium. The estimate channel coefficients are determined from pilot signals and an interpolation process. When the receiver is an OFDM receiver, the pilot signals are advantageously selected to be in clusters that are equally spaced from each other in the time or the frequency domains. This approach applies to multiple antenna, as well as to single antenna arrangements, and to arrangements that do, or do not use space-time coding.
    Type: Grant
    Filed: May 21, 2002
    Date of Patent: October 31, 2006
    Assignee: AT&T Corp.
    Inventors: Naofal Al-Dhahir, Suhas N. Diggavi, Anastasios Stamoulis
  • Publication number: 20060227748
    Abstract: Techniques for deriving a high quality channel estimate are described. A first channel impulse response estimate (CIRE) having multiple channel taps is derived, e.g., by filtering initial CIREs obtained from a received pilot. A threshold parameter value is selected based on at least one criterion, which may relate to channel profile, operating SNR, number of channel taps, and so on. A second CIRE is derived by zeroing out selected ones of the channel taps in the first CIRE based on the threshold parameter value. The average energy of the channel taps may be determined, a threshold may be derived based on the average energy and the threshold parameter value, and channel taps with energy less than the threshold may be zeroed out. A memory may store threshold parameter values for different operating scenarios, and a stored value may be selected for use based on the current operating scenario.
    Type: Application
    Filed: February 10, 2006
    Publication date: October 12, 2006
    Inventors: Anastasios Stamoulis, Durga Malladi
  • Publication number: 20060078075
    Abstract: Techniques for performing data detection and decoding in a manner to account for guard subbands are described. A receiver obtains received pilot symbols for pilot subbands and received data symbols for data subbands. Channel estimates are derived based on the received pilot symbols with zeroed-out pilot subbands filled with zeros. Data detection is performed on the received data symbols with the channel estimates to obtain data symbol estimates. Estimates of noise and estimation errors due to the zeroed-out pilot subbands are derived. LLRs are then computed based on the data symbol estimates, the channel estimates, and the estimates of the noise and estimation errors. The LLRs are deinterleaved and decoded to obtain decoded data.
    Type: Application
    Filed: October 11, 2005
    Publication date: April 13, 2006
    Inventors: Anastasios Stamoulis, Dung Doan, Durga Malladi
  • Publication number: 20060067206
    Abstract: A method and apparatus for communication in a system employing differing transmission protocols. It is determined whether a first time slot of one transmission protocol is adjacent to a second time slot of another transmission protocol, and if a first symbol within the first time slot is adjacent to a second symbol of the second time slot. A pilot power and/or a number of pilot sub-carriers or tones of the first symbol is increased and channel estimation is performed on the first symbol.
    Type: Application
    Filed: September 23, 2005
    Publication date: March 30, 2006
    Inventors: Ashok Mantravadi, Durga Malladi, Avneesh Agrawal, Anastasios Stamoulis
  • Publication number: 20060019653
    Abstract: The disclosure is directed to a mobile communication device, and method for registering with a network from a mobile communications device. A processor in the mobile device may be used to establish a network connection with a server in a network. The mobile device may also include a transceiver that receives information from the server relating to the network connection. The processor may use the information, local measurements, or both to determine whether to register with the network.
    Type: Application
    Filed: June 23, 2005
    Publication date: January 26, 2006
    Inventors: Anastasios Stamoulis, Nikhil Jain
  • Publication number: 20060018279
    Abstract: Frame structures and transmission techniques for a wireless communication system are described. In one frame structure, a super-frame includes multiple outer-frames, and each outer-frame includes multiple frames, and each frame includes multiple time slots. The time slots in each super-frame are allocated for downlink and uplink and for different radio technologies (e.g., W-CDMA and OFDM) based on loading. Each physical channel is allocated at least one time slot in at least one frame of each outer-frame in the super-frame. An OFDM waveform is generated for each downlink OFDM slot and multiplexed onto the slot. A W-CDMA waveform is generated for each downlink W-CDMA slot and multiplexed onto the slot. A modulated signal is generated for the multiplexed W-CDMA and OFDM waveforms and transmitted on the downlink. Each physical channel is transmitted in bursts. The slot allocation and coding and modulation for each physical channel can change for each super-frame.
    Type: Application
    Filed: June 2, 2005
    Publication date: January 26, 2006
    Inventors: Avneesh Agrawal, Durga Malladi, Anastasios Stamoulis, Ashok Mantravadi, Ramaswamy Murali
  • Publication number: 20060018269
    Abstract: To transmit overhead information for broadcast and multicast services in a system that utilizes multiple radio technologies, time slots used for OFDM in a super-frame are initially ascertained. Overhead information for multiple streams to be sent in the time slots used for OFDM is generated. The overhead information conveys the time slots and the coding and modulation used for the streams and may be given in various forms. Multiple records may be formed for the overhead information for the streams. The overhead information for the streams is processed and time division multiplexed with the data for the streams in the super-frame. Information indicating the time slots used for OFDM in the super-frame may be sent separately or included in the overhead information. An indicator may also be appended to each stream to indicate whether there is any change in the overhead information for the stream in the next super-frame.
    Type: Application
    Filed: June 2, 2005
    Publication date: January 26, 2006
    Inventors: Avneesh Agrawal, Durga Malladi, Anastasios Stamoulis, Ashok Mantravadi, Ramaswamy Murali
  • Publication number: 20060013168
    Abstract: Techniques for transmitting data in a wireless communication system are described. Physical channels to be sent in a super-frame are identified and allocated time slots in the super-frame. The coding and modulation for each physical channel are selected based on its capacity. The data for each physical channel is selectively encoded based on an outer code rate, e.g., for a Reed-Solomon code, and further encoded based on an inner code rate, e.g., for a Turbo code. The encoded data for each physical channel is mapped to modulation symbols based on a selected modulation scheme. The modulation symbols for each physical channel are further processed (e.g., OFDM modulated) and multiplexed onto the time slots allocated to the physical channel. Data to be sent using another radio technology (e.g., W-CDMA) is also processed and multiplexed onto time slots allocated for this radio technology.
    Type: Application
    Filed: June 2, 2005
    Publication date: January 19, 2006
    Inventors: Avneesh Agrawal, Durga Malladi, Anastasios Stamoulis, Ashok Mantravadi, Ramaswamy Murali
  • Publication number: 20060013186
    Abstract: Techniques to transmit data with cyclic delay diversity and pilot staggering are described. For cyclic delay diversity, OFDM symbols having different cyclic delay durations are generated. The cyclic delay durations for the OFDM symbols may be selected to be time varying with respect to the cyclic delay durations for OFDM symbols transmitted by a neighboring base station. An FDM pilot is generated and multiplexed on multiple sets of subbands in different symbol periods. Waveforms for a second radio technology (e.g., W-CDMA) may be generated for data to be transmitted with this radio technology. The OFDM symbols are multiplexed onto time slots used for OFDM, and the waveforms for the second radio technology are multiplexed onto time slots used for this radio technology. One or multiple modulated signals may be generated based on the multiplexed OFDM symbols and waveforms. Each modulated signal is transmitted from a respective antenna.
    Type: Application
    Filed: June 2, 2005
    Publication date: January 19, 2006
    Inventors: Avneesh Agrawal, Durga Malladi, Anastasios Stamoulis, Ashok Mantravadi, Ramaswamy Murali
  • Publication number: 20060013325
    Abstract: To transmit data in a manner to mitigate the deleterious effects of delay spread, the expected coverage areas for multiple transmissions to be sent in multiple time slots are initially determined. Cyclic prefix lengths for these transmissions are selected based on the expected coverage areas. The cyclic prefix length for each transmission may be selected from among a set of allowed cyclic prefix lengths based on the expected coverage area for that transmission, the pilot staggering used for the transmission, and so on. For example, a shorter cyclic prefix length may be selected for each local transmission, and a longer cyclic prefix length may be selected for each wide-area transmission. The selected cyclic prefix lengths may be signaled to the terminals. The transmissions are processed (e.g., OFDM modulated) based on the selected cyclic prefix lengths. The cyclic prefix lengths may be selected periodically, e.g., in each super-frame.
    Type: Application
    Filed: June 2, 2005
    Publication date: January 19, 2006
    Inventors: Avneesh Agrawal, Durga Malladi, Anastasios Stamoulis, Ashok Mantravadi, Ramaswamy Murali