Automatic gain control apparatus and method using effective receiving structure of impulse radio ultra-wide band wireless communication system

• US 8,483,334 B2
• Filed: 10/23/2009
• Issued: 07/09/2013
• Est. Priority Date: 11/13/2008
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Oh, Jung-yeol, Kim, Jae Young, Kil, Min Su
• Primary Examiner(s): Fotakis, Aristocratis
• Application Number:
  US12/604,561
• Publication Number:
  US 20100118917A1
• Time in Patent Office: 1,355 Days
• Field of Search: 375/343, 375/318, 375/324, 375/345, 455/245.1, 455/247.1, 455/232.1, 455/242.1, 713/322, 713/323
• US Class Current: 375/345
• CPC Class Codes: H04B 1/71637 Receiver aspects H04B1/7183 takes precedence

Abstract

Provided are an automatic gain control (AGC) apparatus using an efficient receiving structure of an impulse signal-based ultra wideband wireless communication system, and a method thereof. An AGC apparatus of an impulse signal-based wireless communication system guarantees an SNR received through an analog circuit unit, outputs correlation values with respect to an impulse preamble of the received signal, outputs the maximum value of the correlation values for each symbol among the correlation values, or divides a symbol period into a plurality of groups and obtains average values through a sum of each group to output the maximum value thereof.

Claims

1. An automatic gain control (AGC) apparatus in an impulse signal-based wireless communication system, comprising:

a matched filter that attains a signal to noise ratio (SNR) of a received signal received through an analog circuit unit, wherein the matched filter reduces the number of multipliers of a filter in each branch to half by using an even-function symmetry characteristic as given in

2. The AGC apparatus of claim 1, wherein the gain controller receives the attenuation gain output from the comparator to calculate the gains to be changed by applying the attenuation gain to a current gain setting.

3. The AGC apparatus of claim 1, wherein the correlator determines whether a packet is received and synchronization of the packet is acquired by using an output of the matched filter.

4. The AGC apparatus of claim 1, wherein the correlator is realized only by the adder without performing a multiplication operation, and parallel-processes an output of the matched filter.

5. An automatic gain control (AGC) method of an AGC apparatus in an impulse signal-based wireless communication system, comprising:

attaining a signal to noise ratio (SNR) by parallel-processing a signal received through an analog circuit unit and outputting correlation values for impulse preambles of the received signal;

outputting a maximum correlation value at each symbol among the correlation values, or dividing a symbol period into a plurality of groups, obtaining average values through a correlation value sum of each group, and outputting a maximum value among the average values as the maximum correlation value;

comparing the maximum correlation value with at least one predetermined threshold value to determine an attenuation gain, wherein the attenuation gain is determined as Gain=Gain−

step, wherein an attenuation gain step (step) is subtracted from a current gain (Gain);

arranging the correlation values in ascending order in consideration of correlation energy spread due to channel multipaths, and then outputting an average of partial large-sized correlation values as the maximum correlation value;

comparing the average of partial large-sized correlation values with the at least one threshold value and accordingly decreasing the current gain; and

setting or changing gains of a low noise amplifier (LNA) or a variable gain amplifier (VGA) of the analog circuit unit based on the determined attenuation gain;

counting symbols; and

initializing the current gain when a value of the counted symbols is greater than a number of preamble symbols and synchronization is not acquired during a preamble period.

6. The AGC method of claim 5, further comprising, initializing variables related to the gain before the setting the gain of the VGA to an available maximum value.

7. The AGC method of claim 5, further comprising,

determining whether a packet is received, and when the packet is received, determining whether packet receiving is terminated;

determining whether the synchronization is acquired when the packet receiving is not terminated; and

determining whether a current period is an AGC operation period when the synchronization is not acquired,

wherein the comparing the maximum correlation value compares the maximum correlation value with the at least one predetermined threshold value when the current period is an AGC operation period.

8. The AGC method of claim 7, wherein the determining of whether the packet is received is determining whether a packet is received at a receiving unit by comparing the correlation value with the predetermined threshold value.

9. The AGC method of claim 5, wherein the comparing the maximum correlation value comprises:

comparing the maximum correlation value with a first threshold value;

determining the attenuation gain when the maximum correlation value is greater than the first threshold value;

or comparing the maximum correlation value with a second threshold value if the maximum correlation value is not greater than the first threshold value and determining the attenuation gain if the maximum correlation value is greater than the second threshold value.

10. The AGC method of claim 5, wherein, in the setting or changing gains of the LNA or the VGA, a gain set by an abnormal correlation value under a condition that synchronization is not acquired during a preamble period is initialized.

11. An automatic gain control (AGC) apparatus in an impulse signal-based wireless communication system, comprising:

a matched filter that attains a signal to noise ratio (SNR) of a received signal received through an analog circuit unit, wherein when a received input signal is a(k), a coefficient of the matched filter is C_l (l=0, 1, . . . , L−

1) and an output signal is x(k), the matched filter is expressed as given in

12. The AGC apparatus of claim 11, wherein the correlator determines whether a packet is received and synchronization of the packet is acquired by using an output of the matched filter.

13. An automatic gain control (AGC) apparatus in an impulse signal-based wireless communication system, comprising:

a matched filter that attains a signal to noise ratio (SNR) of a received signal received through an analog circuit unit, wherein the matched filter reduces the number of multipliers of a filter in each branch to half by using an even-function symmetry characteristic;

a correlator that outputs correlation signals for a preamble signal of the received signal;

an adder that outputs a maximum correlation value at each symbol among correlation values of the correlation signals or divides a symbol period into a plurality of groups, obtains average values through a correlation value sum of each group, and outputs a maximum value among the average values as the maximum correlation value;

a comparator that compares the maximum correlation value output from the adder with at least one predetermined threshold value to determine an attenuation gain; and

a gain controller that sets or changes gains of a low noise amplifier (LNA) and a variable gain amplifier (VGA) of the analog circuit unit based on the determined attenuation gain,

wherein after determining the attenuation gain by the gain controller, the attenuation gain is initialized when a value of counted symbols is greater than a number of preamble symbols and synchronization is not acquired during a preamble period.

14. An automatic gain control (AGC) method of an AGC apparatus in an impulse signal-based wireless communication system, comprising:

attaining a signal to noise ratio (SNR) by parallel-processing a signal received through an analog circuit unit by a matched filter and outputting correlation values for impulse preambles of the received signal, wherein the matched filter reduced the number of multipliers of a filter in each branch to half by using an even-function symmetry characteristic;

outputting a maximum correlation value at each symbol among the correlation values, or dividing a symbol period into a plurality of groups, obtaining average values through a correlation value sum of each group, and outputting a maximum value among the average values as the maximum correlation value;

comparing the maximum correlation value with at least one predetermined threshold value to determine an attenuation gain, wherein the attenuation gain is determined as Gain=Gain−

step, wherein an attenuation gain step is subtracted from a current gain (Gain);

arranging the correlation values in ascending order in consideration of correlation energy spread due to channel multipaths, and then outputting an average of partial large-sized correlation values as the maximum correlation value;

comparing the average of partial large-sized correlation values with the at least one threshold value and accordingly decreasing the current gain; and

setting or changing gains of a low noise amplifier (LNA) or a variable gain amplifier (VGA) of the analog circuit unit based on the determined attenuation gain;

counting symbols; and

initializing the current gain when a value of the counted symbols is greater than a number of preamble symbols and synchronization is not acquired during a preamble period.