Communication terminal apparatus and demodulation method

• US 20030072253A1
• Filed: 01/04/2002
• Published: 04/17/2003
• Est. Priority Date: 05/19/2000
• Status: Abandoned Application

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Hiramatsu, Katsuhiko
• Application Number:
  US10/019,690
• Publication Number:
  US 20030072253A1
• Time in Patent Office: Days
• US Class Current: 370/206
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 27/3809 Amplitude regulation arrangements

Abstract

A base station apparatus 100 conveys information indicating the ratio of the transmission power of a common known signal (common pilot) included in a common control channel to the transmission power of a signal included in a downlink shared channel to a mobile station apparatus 110-K. Based on this power ratio information, the mobile station apparatus 110-K arranges signal points accurately and performs QAM demodulation with high precision.

Claims

1. A communication terminal apparatus comprising:

signal point arranging means for arranging signal points based on power ratio information which is a ratio of transmission power of a common known signal to transmission power of a signal included in a channel that does not have a known signal; and

demodulating means for performing quadrature amplitude demodulation of received data based on the signal points arranged by said signal point arranging means.

2. The communication terminal apparatus according to claim 1, further comprising extracting means for extracting the power ratio information included in signals transmitted from a base station apparatus, wherein said signal point arranging means arranges the signal points based on the power ratio information extracted by said extracting means.

4. A base station apparatus comprising:

modulating means for switching a modulation method according to an estimated channel condition and modulating transmit data;

power ratio information calculating means for calculating power ratio information which is a ratio of transmission power of a common known signal to transmission power of a signal included in a channel that does not have a known signal; and

transmitting means for transmitting calculated power ratio information to the communication terminal apparatus according to claim 2.

3. A communication terminal apparatus comprising:

signal point arranging means for arranging signal points based on an average power ratio which is a ratio of reception power of a common known signal transmitted from a base station apparatus to an average value for each processing timing of reception power of signals included in a channel that does not have a known signal; and

demodulating means for performing quadrature amplitude demodulation of received data based on signal points arranged by said signal point arranging means.

5. A demodulation method comprising the steps of:

arranging signal points based on power ratio information which is a ratio of transmission power of a common known signal to transmission power of a signal included in a channel that does not have a known signal; and

performing quadrature amplitude demodulation of received data based on arranged signal points.