Lucent Technologies Inc.

Alcatel-lucent USA Inc.

Alcatel Lucent

Alcatel-lucent Technologies Us, Inc.

Angel Lozano

Reinaldo A Valenzuela

Farrokh Rashid-Farrokhi

Howard C Huang

Rainer Walter Bachl

Sergio Verdu

Sivarama Venkatesan

Antonia Maria Tulino

Gerard Joseph Foschini

G J Foschini

Seong-Taek Chung

The present invention provides a method of forming clusters of cells in a wireless communication system. The method includes accessing information generated by measuring channel conditions for at least one mobile unit and a plurality of cells in the wireless communication system. The method also includes adding more than one of the plurality of cells to at least one cell cluster based on the accessed information and coordinating communication between the cells in each cell cluster and the mobile unit(s).

Method for adaptive formation of cell clusters for cellular wireless networks with coordinated transmission and reception

The present invention provides a method of channel estimation implemented in a receiver having multiple antennas configured to receive at least one common pilot available to a plurality of users and a plurality of dedicated pilots. Each dedicated pilot is allocated to one of the plurality of users. The method includes estimating at least one first channel associated with a first user and at least one second channel associated with a second user based on observations of the plurality of dedicated pilots and of said at least one common pilot.

Reverse link channel estimation using common and dedicated pilot channels

In a wireless communication system using multiple antennas at the transmitter and multiple antennas at the receiver, a so called multiple-input multiple-output (MIMO) system, a substantial improvement in capacity over the case of no feedback can be achieved using considerably less bandwidth than is required to feedback the channel estimate or channel statistics, by supplying as feedback for each data substream of an overall data stream an indicator of a rate and/or an indicator of a gain for transmission of that data substream. The indicator of the rate and/or the indicator of the gain may be the rate and/or gain directly or an encoded representation of the rate and/or gain. Typically, the best performance is achieved if indicators of both the rate and the gain are fed back. If the invention is implemented for wireless systems, then typically for each data substream there is a separate, independent antenna. The rate and the gain are computed as a function of a channel estimate which is developed at the receiver. Advantageously, the transmitter may employ only one-dimensional data coding for each of the data substreams.

Feedback technique for wireless systems with multiple transmit and receive antennas

The present invention provides a method implemented in a base station having a plurality of antennas. The method includes associating a plurality of users with a plurality of first pre-coding matrices based on information provided by the plurality of users. The method also includes determining whether at least one of the plurality of first pre-coding matrices is incomplete and associating users with at least one second pre-coding matrix when at least one first pre-coding matrix is incomplete. The users are associated with the incomplete first pre-coding matrix and the second pre-coding matrix is formed based on the incomplete first pre-coding matrix.

Method of grouping users for opportunistic downlink in multiuser, multiple-input-multiple-output wireless communication

Power allocation methods for multiuser orthogonal frequency division multiplexing (OFDM) are described. Arbitrary partitioning of the OFDM tones among users and arbitrary modulation formats, possibly different for every user, are considered. Two systems of receivers and transmitters and corresponding methods address power allocation, respectively for slow fading channels tracked instantaneously by the system and for fast fading channels known only statistically thereby.

Method for allocation of power in multiuser orthogonal frequency division multiplexing

The present invention provides a method of determining a plurality of beamforming weights for application to multicast transmission to a plurality of users by a corresponding plurality of antennas associated with a base station. One embodiment of the method includes determining a covariance matrix associated with the plurality of users. The covariance matrix is determined based on a channel matrix and a noise-plus-interference vector associated with each user. The method also includes determining the plurality of beamforming weights based on a gradient of the covariance matrix associated with a selected one of the plurality of users and storing the plurality of beamforming weights.

Method of transmit beamforming for multicasting in a wireless communication system

The present invention provides a method for supplying unicast and multicast transmissions to a plurality of mobile devices in a wireless system. The method comprises supplying a multicast signal using a first portion of total available power, wherein the first portion of total available power is a function of a channel quality indicator associated with at least one of the mobile devices. Thereafter, a unicast signal is supplied using a second portion of total available power, wherein the second portion of total available power is a function of the first portion of total available power.

Dynamic power allocation for unicast-multicast superposition in wireless broadcasting

In one embodiment, the power for transmitting signals over at least one of a plurality of parallel channels is allocated based on a channel strength threshold and an estimated channel strength for the at least one channel. Here, the channel strength threshold is based on the estimated channel strengths for the plurality of channels.

Method of allocating power over channels of a communication system

In the method, spatial steering of parallel symbol streams and a transmit power of each symbol stream is determined based on a statistical distribution of a channel. The determined spatial steering and transmit powers may then be applied by a transmitter to optimize the transmit signal.

Method for optimizing the transmit signal in multiple antenna wireless links

In a wireless communication system using multiple antennas at the transmitter and multiple antennas at the receiver, with a sufficiently large number of antennas and/or diversity order, the same performance that is obtainable when employing instantaneous rate indication feedback can be attained without any such short-term feedback by adjusting the data rate of each transmit antenna according to a prescribed function. The prescribed function does not depend on the short-term state of the channel, but instead only depends on its long-term statistics, which may be fed back from the receiver to the transmitter at relatively lengthy intervals.

Rate control technique for layered architectures with multiple transmit and receive antennas

Signals are developed for use in a wireless system with multiple transmit and multiple receive antennas so that even in the face of some correlation the most open-loop capacity that can be achieved using a substantially open-loop system with a channel of that level of correlation is obtained. In accordance with the principles of the invention, the signals transmitted from the various antennas are processed so as to improve their ability to convey the maximum amount of information. More specifically, the data to be transmitted is divided into M+1 substreams, where M is the number of transmit antennas. Each transmit antenna is supplied with a combination signal that is made up of a weighted version of a common one of the substreams and a weighted version of a respective one of the substreams that is supplied uniquely for that antenna, so that there are M transmit signals. A receiver having N antennas receives the M transmit signals as combined by the channel and reconstitutes the original data therefrom. This may be achieved using successive decoding techniques. Advantageously, the capacity, i.e., the rate of information that can be conveyed with an arbitrarily small probability of error when the instantaneous forward channel condition is unknown to the transmitter, is maximized.

Space-time processing for wireless systems with multiple transmit and receive antennas

Method and apparatus for communicating heterogeneous data traffic simultaneously using a hybrid Code Division Multiplexing (CDM)/Code Division Multiple Access (CDMA)-Time Division Multiplexing (TDM)/Time Division Multiple Access (TDMA) system which communicates data on a per data type basis, rather than a per user or per channel basis. A transmitter accepts a plurality of data streams, each of which includes either Constant Bit Rate Data (CBR) or Variable Burst Rate Data (VBR), where CBR is characterized by a steady data rate and strict latency requirements and VBR is characterized by a variable data rate with large peaks and lulls and loose latency requirements. The system identifies each input data stream as CBR or VBR. CBR data is spread using CDM/CDMA with an appropriate spreading factor for CBR, whereas VBR data is modulated/encoded and interleaved with CDM/CDMA with an appropriate spreading factor for VBR and TDM/TDMA, respectively. The modulated CBR data and VBR data streams are then transmitted by the transmitter to a receiver, which receives and demodulates the received data streams to recover the original CBR data and VBR data streams. By communicating input data streams based on whether they include CBR data or VBR data, the communication system is able to communicate CBR data and VBR data simultaneously while achieving a superior Quality-of-Service.

Method and apparatus for communicating heterogeneous data traffic

In a MIMO system the signals transmitted from the various antennas are processed so as to improve the ability of the receiver to extract them from the received signal even in the face of some correlation. More specifically the number of bit streams that is transmitted simultaneously is adjusted, e.g., reduced, depending on the level of correlation, while multiple versions of each bit stream, variously weighted, are transmitted simultaneously. The variously weighted versions are combined to produced one combined weighted signal. The receiver processes the received signals in the same manner as it would have had all the signals reaching the receive antennas been uncorrelated. The weight vectors may be determined by the forward channel transmitter using the channel properties of the forward link which are made known to the transmitter of the forward link by being transmitted from the receiver of the forward link by the transmitter of the reverse link or the weight vectors may be determined by the forward channel transmitter using the channel properties of the forward link and the determined weight vectors are made known to the transmitter of the forward link by being transmitted from the receiver of the forward link by the transmitter of the reverse link. The channel properties used to determine the weight vectors may include the channel response from the transmitter to the receiver and the covariance matrix of noise and interference measured at the receiver.

Space-time processing for multiple-input, multiple-output, wireless systems

Signals are developed for use in a wireless system with multiple transmit and multiple receive antennas so that even in the face of some correlation the most open-loop capacity that can be achieved using a substantially open-loop system with a channel of that level of correlation is obtained. In accordance with the principles of the invention, the signals transmitted from the various antennas are processed so as to improve their ability to convey the maximum amount of information. More specifically, the data to be transmitted is divided into M&plus;1 substreams, where M is the number of transmit antennas. Each transmit antenna is supplied with a combination signal that is made up of a weighted version of a common one of the substreams and a weighted version of a respective one of the substreams that is supplied uniquely for that antenna, so that there are M transmit signals. A receiver having N antennas receives the M transmit signals as combined by the channel and reconstitutes the original data therefrom. This may be achieved using successive decoding techniques. Advantageously, the capacity, i.e., the rate of information that can be conveyed with an arbitrarily small probability of error when the instantaneous forward channel condition is unknown to the transmitter, is maximized.

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New York, NY, United States of America

Angel Lozano