Princeton University

Mitsubishi Electric Research Laboratories, Inc.

Texas Instruments Corporation

Worcester Polytechnic Institute

H Vincent Poor

Andreas F Molisch

Sinan Gezici

Hisashi Kobayashi

Triveni N Upadhyay

Stuart C Schwartz

Tandhoni S Rao

Alexander Flaig

John Cangeme

Boyang Zhang

Louis R Brothers, Jr

Donald Richard Brown

Michele Morelli

Luca Sanguinetti

Andrew Logothetis

Mung Chiang

Samuel Jay MacMullan

Visa Koivunen

Hazer Inaltekin

Samuel J MacMullen

Athina Petropulu

Yuanning Yu

A system and method for pricing and exchanging content is provided, which includes a data plane formed by a peer-to-peer content sharing network or a central server allowing for client-server content transfers, and a control plane formed by a central server in communication with the data plane via the Internet. The data plane allows for the storage of digital content provided by users and the transfer of content therebetween, and the control plane provides a virtual market in which such content is sold between users using virtual currency that can be exchanged for real currency.

System and method for pricing and exchanging content

A system and method for initial ranging in wireless communication systems is provided. A plurality of orthogonal frequency division multiplexing (OFDM) blocks are received by an OFDMA base station transceiver from a plurality of remote user devices in wireless communication with the base station. A ranging subchannel is extracted from the OFDM blocks. The number of active codes in the ranging subchannel is determined, active codes are identified, and carrier frequency offsets (CFOs) are estimated for each active code. Timing delays and power levels for each active code are then estimated. The estimated CFOs, timing delays, and power levels are broadcasted by the base station to the remote user devices, so that the user devices can utilize same to adjust transmission parameters to optimize power levels and synchronize communication with the base station.

System and method for initial ranging in wireless communication systems

A system and method for synchronizing the phases and frequencies of devices in multi-user, wireless communications systems are provided. A primary beacon signal is transmitted by a destination node in a wireless communications network to a plurality of source nodes. Secondary beacon signals are also exchanged between the source nodes. Using the primary and secondary beacon signals, the nodes generate local phase and frequency estimates which are used to control local phases and frequencies of the source nodes. The source nodes then transmit common information to the destination at carrier frequencies based on the estimated local frequencies and phases, so that the phases and frequencies of the transmitted information are synchronized to facilitate coherent combining of the bandpass signals at the destination. Phase and frequency synchronization can be applied to wireless communications systems having any number of source nodes, and effects of Doppler shifts and moving platforms are accounted for. Acoustic and radio-frequency signaling can be utilized.

System and method for synchronizing phases and frequencies of devices in multi-user, wireless communications systems

A system and method for blind estimation of carrier frequency offsets (CFOs) and separation of user signals in wireless communications systems are provided. Blind estimation of CFOs (i.e., without knowledge of the conditions of the transmitter or the transmission medium/channel) is carried out in order to improve reception quality by a wireless communications device. A received RF signal is over-sampled by a pre-defined over-sampling factor, and polyphase components are extracted from the over-sampled signal. The polyphase components are used to construct a virtual receiver output matrix, e.g., a model of the received signal and its associated output matrix. System response conditions are blindly estimated by applying a blind system estimation algorithm to the virtual receiver output matrix. A plurality of CFO estimates are obtained from the estimated system response conditions, and can be used by an equalizer to adjust receiver parameters in accordance with the CFO estimates so as to maximize reception quality and to extract multiple user signals from the received signal.

System and method for blind estimation of multiple carrier frequency offsets and separation of user signals in wireless communications systems

In a time-hopped impulse radio system, each symbol is transmitted over a channel having different multipath components as a set of Nframes. Each frame includes one pulse. All frames of a received signal corresponding to the symbol are sampled to generate N&#xd7;L samples, where L is the number of samples for each frame. Then, the N&#xd7;L samples are combined according to a minimum mean square error criterion to obtain a decision variable corresponding to the symbol.

Linear receivers for time-hopping impulse radio systems

A method and system acquire a received impulse radio signal by first searching, with respect to time, a region of the impulse radio signal using a first template signal to locate a block including a signal cell, and second searching, with respect to time, the block using a second template signal to locate the signal cell to acquire the received impulse radio signal.

Method and system for acquiring ultra-wide-bandwidth communications signals using sequential block searches

A method and system acquire a received impulse radio signal by correlating a region, including a plurality of cells, of the received impulse radio signal using multiple time-shifted template signals, each template signal having a different delay to obtain a correlation value for each template signal. The correlation values are averages, and a particular delay associated with a particular template signal having a substantial increase in successive averages to locate a signal cell in the region.

Method and system for acquiring ultra-wide-bandwidth communications signals using average block searches

A first downlink transmission beam and a second downlink transmission beam is determined based on a received user-derived signal. The first downlink transmission beam is substantially uncorrelated with the second downlink transmission beam. The first downlink transmission beam is associated with a portion within a first sector. The second downlink transmission beam is associated with a portion within a second sector. A first signal is diversity encoded to produce a first diversity-encoded signal. A second signal is diversity encoded to produce a second diversity-encoded signal. The first diversity-encoded signal is sent over the first downlink transmission beam. The second diversity-encoded signal is sent over the second downlink transmission beam.

Method and apparatus for received uplinked-signal based adaptive downlink diversity within a communication system

The invention is a switched beam beamforming method and apparatus for wireless communication receiving stations utilizing an array of antenna elements in which only a single beam is generated at any given instant and the beam is switched at a very high rate, e.g., faster than the data rate of the system. An algorithm for scheduling the beamforming sequence is disclosed that optimizes performance by optimizing the signal/interference-plus-noise ratio for a given set of conditions at any instant in time. In particular, spatial diversity offered by antenna arrays for direct sequence-code division multiple access communication systems is exploited by an intelligent switched beam antenna at radio frequency level. The design is optimized to yield conditional mean estimates of the communication channel during uplink transmission and compute minimum variance estimates of the communication channel by optimally combining the signals of the spatially distributed antennas at chip rate.

Method and apparatus for scheduling switched multibeam antennas in a multiple access environment

Method and apparatus for high resolution tracking via mono-pulse beam-forming in a communication system in which the capacity and range of mobile or fixed wireless communication base stations are improved by implementing a single or multiple antenna beam per signal path. Adaptive beam-forming based on up-link direction-of arrival estimation can be performed without using the above-mentioned computationally intensive techniques.

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Princeton, NJ, United States of America

H Vincent Poor