Method of calibrating power for MIMO-OFDM transmitter

• US 10,027,428 B2
• Filed: 02/22/2016
• Issued: 07/17/2018
• Est. Priority Date: 01/25/2016
• Status: Active Grant

• Current Assignee: Innowireless Co., Ltd.
• Original Assignee: Innowireless Co., Ltd.
• Inventors: Joung, Jin Soup, Lee, Joo Hyeong, Lim, Yong Hoon, Jang, Byung Kwan
• Primary Examiner(s): Nowlin, Eric
• Application Number:
  US15/050,007
• Publication Number:
  US 20170214477A1
• Time in Patent Office: 876 Days
• CPC Class Codes: H04B 17/102 Power radiated at antenna
• CPC Class Codes: H04B 17/12 of transmit antennas, e.g. of the amplitude or phase
• CPC Class Codes: H04B 17/13 of power amplifiers, e.g. gain or non-linearity
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04J 11/00 Orthogonal multiplex systems, e.g. using WALSH codesH04J13/00 takes precedence
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Provided is a method of calibrating a power for a multiple input and multiple output-orthogonal frequency division multiplexing transmitter having a plurality of antennas via a measurement equipment, the method including: receiving a cyclic delay diversity (CDD) signal simultaneously output from the transmitter to obtain a starting point of a frame of a corresponding signal; performing a fast Fourier transform on a sample proceeded from the starting point by an extent of a maximum CDD delay; calculating a channel coefficient; calculating a channel impulse response and a power of the channel impulse response; converting CDD delay values of each antenna into values in units of samples by using a sampling rate in the channel impulse response; mapping a peak point position of the channel impulse response to each antenna using CDD delay sample values; and simultaneously performing a power calibration of each antenna based on each peak point power.

Claims

1. A method of calibrating power for a multiple input and multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) transmitter having a plurality of antennas via a measurement equipment coupled to the MIMO-OFDM transmitter, the method comprising:

receiving, via the measurement equipment, a cyclic delay diversity (CDD) signal which is cyclically delayed for a predetermined time period and simultaneously output from the MIMO-OFDM transmitter to obtain a starting point of a frame of a corresponding signal;

performing, via the measurement equipment, a fast Fourier transform (FFT) on a sample preceded by a maximum CDD delay from the starting point of the frame;

calculating, via the measurement equipment, a channel coefficient H(n) by using an FFT calculated training symbol Y(n) and an ideal training symbol X(n), wherein n=0, 1, 2, . . . ;

calculating, via the measurement equipment, a channel impulse response h(k) by performing an inverse fast Fourier transform (IFFT) on the channel coefficient H(n) and calculating a power p(k) of the channel impulse response, wherein k=0, 1, 2, . . . ;

converting, via the measurement equipment, CDD delay values of each antenna into CDD delay sample values by using a sampling rate in the channel impulse response;

mapping, via the measurement equipment, a peak point position of the channel impulse response to each antenna by using the CDD delay sample values; and

simultaneously performing, via the measurement equipment, a power calibration of each antenna based on each peak point power of the plurality of antennas.

2. The method of claim 1, wherein the channel coefficient H(n) is obtained by

3. The method of claim 1, wherein the channel impulse response h(k) and the power p(k) thereof are obtained by

h(k)=IFFT{H(n)}, k=0,1,2, . . . ,FFT size−

1 and

P(k)=real(h(k))*real(h(k))+imag(h(k))*imag(h(k)), k=0,1,2, . . . ,FFT size−

1.

4. The method of claim 2, wherein the channel impulse response h(k) and the power p(k) thereof are obtained by

h(k)=IFFT{H(n)}, k=0,1,2, . . . ,FFT size−

1 and

P(k)=real(h(k))*real(h(k))+imag(h(k))*imag(h(k)), k=0,1,2, . . . ,FFT size−

1.