Synchronization channel noise power estimation

• US 20090034484A1
• Filed: 12/24/2007
• Published: 02/05/2009
• Est. Priority Date: 08/01/2007
• Status: Active Grant

• Current Assignee: Bell Northern Research, LLC (Hilco Inc. (d/b/a Hilco Global))
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Wu, Jun, Kong, Hongwei
• Granted Patent: US 8,050,237 B2
• Time in Patent Office: Days
• US Class Current: 370/335
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 7/0871 using different reception schemes, at least one of them being a diversity reception scheme
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Apparatus and method to process a pilot channel and a synchronization channel to obtain a combined noise estimate of the pilot channel and the synchronization channel that is synchronized to the pilot channel. The combined noise estimation is processed to determine a first noise component for a period when both the pilot channel and the synchronization channel are present. Then, the combined noise estimate is processed to determine a second noise component for a period when only the pilot channel is present. Next, the second noise component is subtracted from the first noise component to derive a noise estimation for the synchronization channel. The technique may be applied to the Common Pilot Channel (CPICH), and the Synchronization Channel (SCH) defined in a 3^rd Generation Partnership Project standard specification.

Claims

1. An apparatus comprising:

a pilot processing module to obtain combined noise estimation of a pilot channel and a synchronization channel that is synchronized to the pilot channel;

a first processing module coupled to receive the combined noise estimation and from the combined noise estimation, the first processing module to determine a first noise component for a period when both the pilot channel and the synchronization channel are present; and

a second processing module coupled to receive the combined noise estimation and from the combined noise estimation, the second processing module to determine a second noise component for a period when only the pilot channel is present.

2. The apparatus of claim 1, wherein the first processing module averages the combined noise estimation over a first pre-defined set of symbols to determine the first noise component and the second processing module averages the combined noise estimation over a second pre-defined set of symbols to determine the second noise component.

3. The apparatus of claim 2 further including a third processing module to subtract the second noise component from the first noise component to derive a noise estimation for the synchronization channel.

4. The apparatus of claim 3, wherein the pilot processing module utilizes one signal processing path to obtain the combined noise estimation when receiving a non-diversity signal and utilizes multiple signal processing paths when receiving a diversity signal to process channels separately, wherein estimations from the dual paths are subsequently combined to obtain the combined noise estimation.

5. The apparatus of claim 3, wherein the noise estimation for the synchronization channel is utilized to compensate noise power in the synchronization channel in determining a signal-to-noise ratio (SNR) calculation of another signal component.

6. The apparatus of claim 5, wherein the synchronization channel has a timing offset with the another signal component, in which the noise power compensation of the synchronization channel is adjusted by the amount of the timing offset relative to the another signal component in determining the SNR.

7. The apparatus of claim 6, wherein the pilot channel and the synchronization channel are transmitted from a base station of a wireless communication network.

8. The apparatus of claim 7, wherein the pilot channel is a Common Pilot Channel (CPICH), and the synchronization channel is a Synchronization Channel (SCH) defined in a 3^rd Generation Partnership Project standard specification.

9. The apparatus of claim 3, wherein the synchronization channel is present for approximately 1/10 of a duration of a slot of the pilot channel.

10. An apparatus comprising:

a pilot processing module to obtain combined noise estimation of a downlink common pilot channel having multiple slots and a downlink synchronization channel that is synchronized to a beginning of each slot of the pilot channel, but present for only a portion of each slot;

a first processing module coupled to receive the combined noise estimation and to average the combined noise estimation over a first pre-defined set of symbols for a slot to determine a first noise component for a period when both the pilot channel and the synchronization channel are present; and

a second processing module coupled to receive the combined noise estimation and to average the combined noise estimation over a second pre-defined set of symbols for the slot to determine a second noise component for a period when only the pilot channel is present.

11. The apparatus of claim 10 further including a third processing module to subtract the second noise component from the first noise component to derive a noise estimation for the synchronization channel.

12. The apparatus of claim 10, wherein the pilot channel is a Common Pilot Channel (CPICH), and the synchronization channel is a Synchronization Channel (SCH) defined in a 3^rd Generation Partnership Project standard specification.

13. The apparatus of claim 10, wherein the synchronization channel is present for approximately 1/10 of a duration of each slot of the pilot channel.

14. The apparatus of claim 12, wherein the first pre-defined set of symbols is first two symbols of each slot of CPICH and the second pre-defined set of symbols is the remaining symbols of each slot of CPICH.

15. Method comprising:

processing a pilot channel and a synchronization channel to obtain a combined noise estimation of the pilot channel and the synchronization channel that is synchronized to the pilot channel;

processing the combined noise estimation to determine a first noise component for a period when both the pilot channel and the synchronization channel are present; and

processing the combined noise estimation to determine a second noise component for a period when only the pilot channel is present.

16. The method of claim 15, wherein processing the combined noise estimation averages the combined noise estimation over a first pre-defined set of symbols to determine the first noise component and averages the combined noise estimation over a second pre-defined set of symbols to determine the second noise component.

17. The method of claim 16 further including subtracting the second noise component from the first noise component to derive a noise estimation for the synchronization channel.

18. The method of claim 17 further including applying the derived noise estimation for the synchronization channel to a signal component that is transmitted during a period that the pilot channel and synchronization channel are transmitted to compensate for additional noise introduced by the synchronization channel when the synchronization channel is present.

19. The method claim 18, wherein the pilot channel is a Common Pilot Channel (CPICH), and the synchronization channel is a Synchronization Channel (SCH) defined in a 3^rd Generation Partnership Project standard specification.

20. The method of claim 19 further including adjusting for a timing offset between SCH and a signal component of a Dedicated Physical Channel (DPCH) defined in a 3^rd Generation Partnership Project standard specification and compensating for noise power in SCH overlapping the DPCH signal component to calculate a signal-to-noise ratio (SNR).