Method and apparatus for gain equalization based on wide-band multi-carrier base station

• US 20030228845A1
• Filed: 04/28/2003
• Published: 12/11/2003
• Est. Priority Date: 11/14/2000
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Peng, Qingquan, Gui, Yijun
• Granted Patent: US 7,099,626 B2
• Time in Patent Office: Days
• US Class Current: 455/67.11
• CPC Class Codes: H04L 27/2637 with direct modulation of individual subcarriers
• CPC Class Codes: H04L 27/367 using predistortion
• CPC Class Codes: H04W 52/10 Open loop power control
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

A method and apparatus of gain equalization based on a wide-band multi-carrier base station calculates or tests non-uniformity of a gain of an analog intermediate frequency and a radio frequency in advance and stores corresponding correction values in tables. In an initialization period before operating, the corresponding correction values are looked up from the tables based on the analog intermediate frequency and the radio frequency corresponding to each of the carriers to implement a specific correction in a multiplier of a digital up-converter before interpolation. Under a premise that hardware is not modified and specification is not degraded, the non-uniformity of the amplitude-frequency characteristic of the respective carriers in shared channels of a transmitter is equilibrated or corrected by changing a gain-adjust-coefficient of the respective carriers, thereby significantly improving the consistency of the gain of the respective carriers and reducing consumption of resources.

Claims

1. A method of gain equalization based on a wide-band multi-carrier base station, comprising the steps of:

a) calculating a gain of respective carriers at an output port of a digital to analog converter (DAC) and normalizing to obtain a first gain correction factor table with a plurality of respective first gain correction factors;

b) testing the gain of the respective carriers in a radio frequency portion and normalizing to obtain a second gain correction factor table with a plurality of respective second gain correction factors;

c) storing the first and second gain correction factor tables; and

d) looking up a first gain correction factor from the first gain correction factor table and a second gain correction factor from the second gain correction factor table corresponding to each of the carriers, and multiplying the first gain correction factor with the second gain correction factor, and using multiplied result as a gain-adjust-coefficient of the respective carrier.

2. The method of claim 1, wherein the step of obtaining the first gain correction factors comprises the steps of:

within an intermediate frequency bandwidth of f1˜

f2, calculating amplitude values of interpolating function (Sin x/X) corresponding to frequency points of the respective carriers according to a minimum channel space of a step Δ

, using an intermediate frequency f1 as a reference to normalize the amplitude values of the frequency points of the respective carriers, and taking reciprocal values to obtain the first gain correction factors of intermediate frequency points.

3. The method of claim 2, wherein the intermediate frequency f1 is integral multiples of a minimum channel space step Δ

.

4. The method of claim 2, wherein frequency of the frequency points of the respective carriers is f1+mΔ

, and there are totally (f2−

f1)/Δ

+1 points, m is an integral number.

5. The method of claim 1, wherein the step of obtaining the second gain correction factors comprises the steps of:

outputting one of the carriers with a proper level by the DAC to the radio frequency portion through setting;

changing a local oscillator frequency, varying a final output signal arbitrarily with a step Δ

within a frequency bandwidth f3−

f4, testing corresponding gain values to find a maximum value, using the maximum value as a reference to normalize the gain values of frequency points of the respective carriers; and

taking reciprocal values to obtain the second gain correction factors of the frequency points of the radio frequency portion.

6. The method of claim 5, wherein frequency of the frequency points of the respective carriers is f3+mΔ

, and there are totally (f4−

f3)/Δ

+1 points, m is an integral number.

7. The method of claim 2, wherein the intermediate frequency points of the respective carriers are controlled by a numerical control oscillator (NCO) in a digital up-converter (DUC), and setting of frequency of a radio frequency oscillator is completed in the intermediate frequency bandwidth.

8. The method of claim 1, wherein the second gain correction factor table is obtained from a voltage detection at an output port of a power amplifier.

9. The method of claim 1, wherein the second gain correction factor table is obtained from a power detection at an output port of a power amplifier.

10. An apparatus of gain equalization based on a wide-band multi-carrier base station having a transmitter system, comprising:

a plurality of base-band processing portions;

a plurality of digital up-converters (DUCs);

a multiple synthesizing summer;

a digital to analog converter (DAC);

a wide-band transmitter;

a wide-band power amplifier; and

an output antenna;

wherein outputs of the plurality of the base-band processing portions are connected to each of the base-band processing portions, respectively, outputs of the DUCs are connected to the multiple synthesizing summer, and the multiple synthesizing summer, the DAC, the wide-band transmitter, the wide-band power amplifier, and the output antenna are connected sequentially.

11. The apparatus of claim 10, wherein each of the DUCs comprises:

a modulator;

a gain adjustment digital multiplier;

an interpolation filter;

a high rate digital multiplier; and

a numerical control oscillator;

wherein each of the outputs of the base-band processing portions is connected to the modulator, and the modulator, the gain adjustment digital multiplier, the interpolation filter, and the high rate digital multiplier are connected sequentially, first and second gain correction factors are sent to the gain adjustment digital multiplier, respectively, and an output of the numerical control oscillator is sent to the high rate digital multiplier.

12. The apparatus of claim 11, wherein the gain adjustment digital multiplier includes first and second low rate digital multipliers connected in series.

13. The apparatus of claim 11, wherein the first and second gain correction factors of the respective carriers are obtained by looking up a DAC gain correction factor table and a radio frequency gain correction factor table.

14. The apparatus of claim 13, wherein the radio frequency gain correction factor table is obtained from a voltage detection at an output port of the wide-band power amplifier.

15. The apparatus of claim 13, wherein the radio frequency gain correction factor table is obtained from a power detection at an output port of the wide-band power amplifier.