Method and apparatus for channel estimation using plural channels

• US 20030099306A1
• Filed: 11/28/2001
• Published: 05/29/2003
• Est. Priority Date: 11/28/2001
• Status: Active Grant

• Current Assignee: Optis Wireless Technology, LLC (Brevet Capital)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Bernhardsson, Bo, Nilsson, Johan, Eriksson, Hakan
• Granted Patent: US 7,346,126 B2
• Time in Patent Office: Days
• US Class Current: 375/316
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0212 of impulse response
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel

Abstract

Methods and apparatus are described for estimating a gain offset between two channels in a communication system. The gain offset arises from the system'"'"'s transmission of signals on the two channels at different powers. The estimated gain offset is used for determining a set of complex channel estimates.

Claims

1. A method of determining a gain offset between transmission channels in a communication system, comprising the steps of:

deriving a first set of channel estimates from symbols received through a first channel;

deriving a second set of channel estimates from symbols received through a second channel; and

determining the gain offset based on the first and second sets of channel estimates.

2. The method of claim 1, wherein the first and second channels are pilot channels.

3. The method of claim 1, wherein the first and second channels are a DPCH and CPICH, respectively.

4. A method of determining a set of complex channel estimates for a transmission channel in a communication system, comprising the steps of:

deriving a first set of channel estimates from symbols received through the transmission channel;

deriving a second set of channel estimates from symbols received through a second channel in the communication system;

determining a gain offset based on the first and second sets of channel estimates; and

determining the set of complex channel estimates based on the gain offset and the first and second sets of channel estimates.

5. The method of claim 4, wherein the gain offset is determined using a second-order equation.

6. The method of claim 4, wherein the gain offset g^ML is determined using the following equation:

7. The method of claim 6, wherein the complex channel estimate h_i^ML is determined using the following equation:

8. The method of claim 6, wherein the complex channel estimate is determined by performing a linear combination of the first and second set of channel estimates based on the gain offset.

9. A method of determining a set of channel estimate gains for a transmission channel in a communication system, comprising the steps of:

deriving a first set of channel estimates from symbols received through the transmission channel;

deriving a second set of channel estimates from symbols received through a second channel in the communication system;

determining a gain offset based on the first and second sets of channel estimates;

determining a set of channel estimate gains based on the gain offset and the first and second sets of channel estimates; and

associating the set of channel estimate gains with channel estimate phases of one of the first and second sets of channel estimates.

10. The method of claim 9, wherein the associated channel estimate phase is the one of the first and second sets of channel estimates being from a high-power channel.

11. The method of claim 10, wherein the associated channel estimate phase is the one of the first and second sets of channel estimates being from a DPCH channel.