Multi-path interference removing for wireless relay system apparatus and method using by same channel frequency

• US 20060013183A1
• Filed: 05/09/2005
• Published: 01/19/2006
• Est. Priority Date: 07/14/2004
• Status: Active Grant

• Current Assignee: RF Window Co., Ltd.
• Original Assignee: RF Window Co., Ltd.
• Inventors: Song, Ju Tae, Kang, Hyun, Lee, Seong Jae
• Granted Patent: US 7,486,933 B2
• Time in Patent Office: Days
• US Class Current: 370/343
• CPC Class Codes: H04B 7/15564 Relay station antennae loop interference reduction

Abstract

Embodies of peripheral a wireless relay system apparatus and method for a multi-path interference removing using by same channel frequency is shown and described, which purpose of the present invention is to overcome extension of service coverage and a dead spot with amplifying same channel frequency, a problem in doing the relay, system wireless relay system was a same frequency interference of RF (Radio Frequency) output is become feedback radiating from tx antenna to rx antenna of the relay system, the wireless relay system apparatus and method effectively eliminates the same frequency interference so that it can ensure an additional system gain and easy to set up relatively to general same frequency relay system.

Claims

1. In wireless relay system that get rid of multi-path interference signal using by same channel frequency that comprising:

a rx antenna which is receiving same frequency of wireless channel;

a rx band pass filter which is only passes received signal through the rx antenna;

a rx low noise amplifier which is received RF(Wireless Frequency) signal as needed through the rx band pass filter;

a rx down converter which is receiving amplified signal through the rx low noise amplifier;

a digital signal process which converts a IF frequency to be able to processes the digital signal in the rx down converter;

a rx up converter which converts a clear IF signal to received signal by interference removing from the digital signal process;

a linear power amplifier which converts receiving signal to RF signal by the rx up converter;

a tx band pass filter which is receiving amplified RF signal by the linear power amplifier;

a multi-path interference cancellation controller for wireless relay system using by same channel frequency, which consists of tx antenna for radiating RF signal through the passing filter for transmitting signal.

2. The multi-path interference removing apparatus of wireless relay system as in claim 1, wherein multi-path interference removing apparatus of wireless relay system using by same channel frequency further comprises a generating of feedback for the radiating same channel frequency through the tx antenna, said same channel frequency is receiving multi-path interference frequency in rx antenna, wherein f1_d and f1_m1 through f1_mn of interference signal.

3. The multi-path interference removing apparatus of wireless relay system as in claim 1, wherein multi-path interference removing apparatus of wireless relay system using by same channel frequency further comprises the digital signal process consists of estimator #1 through #N, and a multi-path interference cancellation controller to be able to eliminate interference signal by mixing in rx with summing to create amplitude and reverse-phase of interference signal to apply algorithm to same time delay for eliminating the interference signal.

4. The multi-path interference removing apparatus of wireless relay system as in claim 3, wherein multi-path interference removing apparatus of wireless relay system using by same channel frequency further comprises the detecting time delay algorithm executes with power on, and apply to search for a location of interference in an appropriate estimator to modify a digital signal gain, said applied location of interference is looking for a minimum of the multi-path interference, then consistently to be executed detecting time delay algorithm to apply the digital signal gain.

5. In a wireless relay system for multi-path interference removing method, the wireless relay system method comprising:

a step 1 in which is coupling through monitoring coupler of emitting output from tx antenna;

a step 2 in which transmits into rx down converter coupled signal of the step 1;

a step 3 in which transmits the signal of rx down converter into digital signal process;

a step 4 in which converts transmitted signal from the step 3 into digital signal from ADC (Analog to Digital Converter);

a step 5 in which analysis a time delay of a same channel multi-path interference signal from converted digital signal of the step 4 in a interference cancellation controller;

a step 6 in which creates a reverse-phase of a same amplitude with from analysis signal of the step 5 having a time delay which is the same with multi-path interference signal;

a step 7 in which eliminates multi-path interference signal using by same channel frequency with summing created reverse-phase signal of the step 6.

6. The multi-path interference removing method of wireless relay system as in claim 5, wherein the same channel multi-path interference signal of said step 5 further comprises:

f1_—

d=f1_—

tx+antenna cable delay+air delay between tx/rx antenna
f1_—

m1=f1_—

tx+antenna cable delay+air delay by reflector 1
f1_—

m2=f1_—

tx+antenna cable delay+air delay by reflector 2
f1_—

mn=f1_—

tx+antenna cable delay+air delay by reflector n

7. The multi-path interference removing method of wireless relay system as in claim 5, wherein multi-path interference signal using by same channel frequency further comprising said step 6 creates an interference signal to calculate time delay of multi-path interference signal, and creates a reverse-phase, which is consisting of amplitude and 180 degree of the interference signal.

8. The multi-path interference removing method of wireless relay system as in claim 5, wherein multi-path interference signal using by same channel frequency further comprising said step 7 executes algorithm if power on using algorithm of detecting time delay, then apply to search for a location of interference in an appropriate estimator to modify a digital signal gain, and then check the applied location of interference, which is looking for a minimum of the multi-path interference, and then consistently to be executed detecting time delay algorithm to apply the digital signal gain, so that eliminates multi-path interference with summing of generating confirmed interference, same amplitude, and reverse-phase.