Alcatel-lucent USA Inc.

Nokia Technologies Oy

Alcatel Lucent

Ajit Reddy

Dragan Samardzija

Cuong Tran

Robert Fairfield

A switched-beam communication node (e.g., transmitter, receiver, or transceiver) has an antenna array, an (N&#xd7;N) passive multibeamformer (e.g., Butler matrix (BM)), a phase network, a switch network, and a controller. The phase network has N phase shifters, one for each different beam port of the Butler matrix. The controller configures the node to support either (i) any one of N main beampatterns supported by the Butler matrix by controlling the switch network to select one of the phase shifters and its corresponding BM beam port or (ii) any one of up to at least (N&#x2212;1) combined beampatterns by controlling the switch network to select two of the phase shifters and their two corresponding BM beam ports. Each combined beampattern is a combination of two phase-shifted main beampatterns. In some embodiments, the node can be configured to provide two concurrent beampatterns for transmit and/or receive operations, thereby supporting space-division multiple-access systems.

Switched-beam communication node

A processor receives a first vector signal and a second vector signal from a circuit in response to the circuit receiving the first vector signal. The processor transforms the second vector signal from a time domain to a transform domain. The processor rotates the transformed second vector signal by a phase that is proportional to a time delay between the first and second vector signals to time-align the second vector signal to the first vector signal.

Vector signal alignment for digital vector processing using vector transforms

A fractional delay estimation module estimates a delay of a section of a forward processing path between a first point and a second point. The fractional delay estimation component determines an integer component and a fractional component of a first path delay based on a transform of a first vector inserted into the forward processing path at the first point and based on a transform of a first feedback vector received from a feedback path, determines an integer component and a fractional component of a second path delay in the forward processing path based on a third transform of a third vector inserted into the forward processing path at the second point and based on a fourth transform of a second feedback vector received from the feedback path, and further determines the estimated delay of the section based on a difference between the first and second path delays.

Fractional delay estimation for digital vector processing using vector transforms

A method includes transmitting, at a first time, a first transmission vector signal towards an antenna via a feeder cable connected to the antenna; receiving a first reflected vector signal, the first reflected vector signal being a reflection of the first transmission vector signal reflected from a point in the feeder cable; determining a first transformed transmission vector signal by performing a first vector forward transform on the first transmission vector signal; determining a first transformed reflected vector signal by performing a first vector forward transform on the first reflected vector signal; determining a first complex conjugate vector signal based on the first transmission vector signal and the first reflected vector signal; determining a first computed vector signal by performing a first vector inverse transform on the first complex conjugate vector signal; and determining a first sub-vector by performing a windowing function based on the first computed vector signal.

Growing community of inventors

Cliffwood, NJ, United States of America

Ajit Reddy