Apparatus and method for estimating a signal power to interference power ratio in a wireless communication system

• US 20060045195A1
• Filed: 09/02/2005
• Published: 03/02/2006
• Est. Priority Date: 09/02/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Ok, Kwang-Man, Kang, Chung-Gu, Kim, Min-Goo, Rho, Wi-Sang
• Granted Patent: US 7,400,896 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/26265 Arrangements for sidelobes suppression specially adapted to multicarrier systems, e.g. spectral precoding

Abstract

A transmission and reception apparatus and method for use in a wireless communication system, and an apparatus and method for adaptively transmit and receive a signal according to channel state in a wireless communication system. An apparatus for adaptively performing transmission according to a state of a channel transmitted from a transmitter to at least one receiver includes a signal to interference ratio estimator for estimating a signal to interference ratio of the channel using a signal transmitted from the at least one receiver; and an adaptive transmitter for transmitting data to the at least one receiver on a basis of the estimated signal to interference ratio.

Claims

1. An apparatus for adaptively performing transmission according to a state of a channel transmitted from a transmitter to at least one receiver, comprising:

a signal to interference ratio estimator for estimating a signal to interference ratio of the channel using a signal transmitted from the at least one receiver; and

an adaptive transmitter for transmitting data to the at least one receiver based on the estimated signal to interference ratio.

2. The apparatus of claim 1, wherein the signal transmitted from the at least one receiver is a pilot symbol.

3. The apparatus of claim 1, wherein the signal to interference ratio estimator despreads signals received from a plurality of receivers and signal to interference ratios of channels between the transmitter and the plurality of receivers.

4. The apparatus of claim 3, wherein the signal to interference ratio estimator comprises:

a multipath profile measurer for measuring a delay time and intensity of signals transmitted from a receiver through various paths;

a fast Fourier transform (FFT) processor for for acquiring a channel transfer function by fourier-transforming a multipath profile;

an interference estimator for estimating a distance between the transmitter based on the delay time and the receiver and estimating interference power between the transmitter and the receiver according to the distance; and

a signal power to interference power ratio calculator for calculating a signal power to interference power ratio using a ratio of a signal output from the FFT processor and a signal output from the interference estimator.

5. An apparatus for adaptively performing transmission and reception according to a state of a channel transmitted from a transmitter to a receiver, comprising:

an adaptive transmitter for estimating a signal to interference ratio for the receiver using a pilot symbol transmitted from the receiver and adaptively performing transmission according to the signal to interference ratio; and

an adaptive receiver for transmitting a pilot symbol spread with a unique pseudo noise code to the adaptive transmitter, calculating a channel estimate of a signal transmitted from the adaptive transmitter, and adaptively receiving the transmitted signal.

6. The apparatus of claim 5, wherein the adaptive receiver comprises:

a transmitter for transmitting the pilot symbol spread with the unique pseudo noise code;

a channel estimator for estimating a channel state using the signal received from the adaptive transmitter; and

a receiver for receiving the signal on a basis of the channel estimate.

7. The apparatus of claim 6, wherein the transmitter comprises:

a multiplexer for multiplexing input user data and known pilot data and outputting a result of the multiplexing; and

a spreader for spreading an output of the multiplexer with a unique pseudo noise code and outputting a result of the spreading.

8. The apparatus of claim 6, wherein the transmitter comprises:

a spreader for spreading known pilot data with a unique pseudo noise code and outputting a result of the spreading; and

a multiplexer for multiplexing input user data and the spread pilot data and outputting a result of the multiplexing.

9. A method for adaptively performing transmission according to state of a channel transmitted from a transmitter to a receiver, comprising the steps of:

transmitting a pilot symbol spread with a unique pseudo noise code from the receiver to the transmitter;

receiving the pilot symbol and estimating a signal to interference ratio of the channel in the transmitter; and

adaptively transmitting a signal from the transmitter to the receiver according to the estimated signal to interference ratio.

10. The method of claim 9, further comprising the steps of:

estimating a channel state of the signal received from the transmitter in the receiver; and

adaptively receiving the signal in the receiver on a basis of a channel estimate.

11. The method of claim 9, wherein the step of estimating the signal to interference ratio comprises the steps of:

measuring a delay time and intensity of signals transmitted from a receiver through various paths;

acquiring a channel transfer function by fourier-transforming a multipath profile;

estimating a distance between the transmitter and the receiver based on the delay time and estimating interference power between the transmitter and the receiver according to the distance; and

calculating a signal power to interference power ratio using a ratio of a signal output from an FFT processor and a signal output from an interference estimator.

12. A computer readable medium having a set of instructions for adaptively performing transmission according to a state of a channel transmitted from a transmitter to a receiver, comprising:

a first set of instructions for transmitting a pilot symbol spread with a unique pseudo noise code from the receiver to the transmitter;

a second set of instructions for receiving the pilot symbol and estimating a signal to interference ratio of the channel in the transmitter; and

a third set of instructions for adaptively transmitting a signal from the transmitter to the receiver according to the estimated signal to interference ratio.

13. The computer readable medium having a set of instructions further comprising:

a fourth set of instructions for estimating a channel state of the signal received from the transmitter in the receiver; and

a fifth set of instructions for adaptively receiving the signal in the receiver on a basis of a channel estimate.