Structured-pipelined CORDIC for matrix equalization
AssigneeNXP USA, Inc.
InventorsYong Ma, Kai Cheong Tang, Chao Shan, Mao Yu
Life of this patent
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Abstract
Flexible structured-pipelined CORDIC techniques efficiently perform various CORDIC operations and support different parameters for MIMO MEQ processing. The structured-pipelined CORDIC techniques simplify signal processing flow, unify input requirements and output delay, and simplify integration. Look-up table techniques provide quick generation of control signals, reduce design and verification efforts, and facilitate design automation. In addition, the structured-pipelined CORDIC techniques are conducive to hardware sharing and reuse. The structured-pipelined CORDIC techniques reduce integrated circuit area and power consumption.
Claims20
A Multiple-Input, Multiple-Output (MIMO) Orthogonal Frequency-Division Multiplexing (OFDM) receiver comprising:
- a structured-pipelined COordinate Rotation Digital Computer (CORDIC) configured to generate an output real signal, an output imaginary signal, and an output rotation signal, the structured-pipelined CORDIC comprising:
- a first input selection circuit configured to output a first input real signal selected from M input real signals according to an input selection signal where M is an integer greater than zero;
- a second input selection circuit configured to output a first input imaginary signal selected from M input imaginary signals according to the input selection signal;
- a third input selection circuit configured to output a first input rotation signal selected from M−1 input rotation signals and the output rotation signal according to the input selection signal;
- and
- I CORDIC stages coupled in series comprising:
- a first CORDIC stage configured to receive the first input real signal, the first input imaginary signal, the first input rotation signal, and an input control signal, and
- I−1 additional CORDIC stages, each of the I−1 additional CORDIC stage being configured to receive a corresponding output real signal, a corresponding output imaginary signal, a corresponding output rotation signal, and a corresponding stored control signal of a prior adjacent CORDIC stage of the I CORDIC stages,
- wherein the output real signal, the output imaginary signal, and the output rotation signal are based on a last output real signal, a last output imaginary signal, a last output rotation signal, respectively, generated by a last CORDIC stage of the I−1 additional CORDIC stages, where I is a second integer greater than one.
A method for operating A Multiple-Input, Multiple-Output (MIMO) Orthogonal Frequency-Division Multiplexing (OFDM) receiver, the method comprising:
- generating an output real signal, an output imaginary signal, and an output rotation signal by performing a structured-pipelined CORDIC operation comprising:
- selecting a first input real signal from M input real signals according to an input selection signal, where M is an integer greater than one;
- selecting a first input imaginary signal from M input imaginary signals according to the input selection signal;
- selecting a first input rotation signal from M−1 input rotation signals and the output rotation signal according to the input selection signal;
- performing I iterations of a CORDIC operation comprising:
- performing a first iteration of the CORDIC operation on the first input real signal, the first input imaginary signal, and the first input rotation signal according to an input control signal;
- and
- performing I−1 additional iterations of the CORDIC operation, each of the I−1 additional CORDIC operations including receiving a corresponding output real signal, a corresponding output imaginary signal, a corresponding output rotation signal, and a corresponding stored control signal of a prior contiguous CORDIC operation of the I CORDIC operations,
- wherein the output real signal, the output imaginary signal, and the output rotation signal are based on a last output real signal, a last output imaginary signal, a last output rotation signal, respectively, generated by a last CORDIC operation of the I−1 additional CORDIC operations.
A method for matrix equalization in a Multiple-Input, Multiple-Output (MIMO) Orthogonal Frequency-Division Multiplexing (OFDM) receiver comprising:
- for each subcarrier of an OFDM signal, determining NSS upper triangular matrices of a channel matrix by using structured-pipelined CORDICs,
- wherein the channel matrix is an M×NSS matrix, M is a number of receiver antennas used to receive a received packet by the receiver, NSS is a number of information streams received in the received packet, and M≥NSS;
- generating an output real signal, an output imaginary signal, and an output rotation signal by performing a structured-pipelined CORDIC operation by a structured-pipelined CORDIC of the structured pipelined CORDICs, performing the structured-pipelined CORDIC operation comprising
- generating an output real signal, an output imaginary signal, and an output rotation signal by performing a structured-pipelined CORDIC operation comprising:
- selecting a first input real signal from M input real signals according to an input selection signal, where M is an integer greater than one;
- selecting a first input imaginary signal from M input imaginary signals according to the input selection signal;
- selecting a first input rotation signal from M−1 input rotation signals and the output rotation signal according to the input selection signal.
Dependencies are inferred from the claim text.