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

• US 7,400,896 B2
• Filed: 09/02/2005
• Issued: 07/15/2008
• Est. Priority Date: 09/02/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Rho, Wi-Sang, Ok, Kwang-Man, Kang, Chung-Gu, Kim, Min-Goo
• Primary Examiner(s): Anderson; Matthew
• Assistant Examiner(s): DAO, MINH D
• Application Number:
  US11/217,669
• Publication Number:
  US 20060045195A1
• Time in Patent Office: 1,047 Days
• Field of Search: 455/506, 455/63.1, 455/65, 455/10, 455/18, 455/67.16, 455/242.2, 455/243.2, 455/114.2, 370/335, 370/252, 375/240.18, 375/149
• US Class Current: 455/506
• 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

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 despreading signals, spread by the unique code of the receiver from the at least one receiver, using the unique code, measuring a multipath profile represented a delay time and signal strength of downlink signal transmitted through the multipath between the transmitter and the receiver from the despreading signals, transforming a multipath profile according to the FFT and acquiring a channel transfer function, estimating a distance between the transmitter and the receiver according to the delay time and estimating interference power between the transmitter and the receiver according to the distance, and estimating a signal to interference ratio of the subchannels of the receiver using a ratio of a the signal FFT processed and the estimated interference power; 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 spread 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. 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 measuring a multipath profile represented a delay time and signal strength of downlink signal transmitted through the multipath between the transmitter and the receiver using a pilot symbol spread with a unique code from the receiver, transforming a multipath profile according to the FFT and acquiring a channel transfer function, estimating a distance between the transmitter and the receiver according to the delay time and estimating interference power between the transmitter and the receiver according to the distance, and estimating a signal to interference ratio of the subchannels of the receiver using a ratio of a the signal FFT processed and the estimated interference power and adaptively performing data 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 using the calculated channel estimate.

5. The apparatus of claim 4, 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.

6. The apparatus of claim 5, 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.

7. The apparatus of claim 5, 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.

8. 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 spread with the unique pseudo noise code;

measuring a multipath profile represented a delay time and signal strength of downlink signal transmitted through the multipath between the transmitter and the receiver from the despreading pilot symbol;

transforming a multipath profile according to fast Fourier transform (FFT) and acquiring a channel transfer function;

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

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 in the transmitter; and

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

9. The method of claim 8, 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.