# US 8,787,510 B2 · Channel selection exploiting multiple observations of the channel delay spread

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- Number: US 8,787,510 B2
- Document ID: US8787510B2
- Status: Granted
- Kind: B2
- Application number: 12/649,611
- Filed: 2009-12-30
- Published: 2010-07-08
- Granted: 2014-07-22
- Earliest claimed: 2008-12-31
- Assignees: Motorola Mobility LLC
- Applicants: Sandeep Krishnamurthy; Colin Frank; Kenneth Stewart
- Inventors: Sandeep Krishnamurthy; Colin Frank; Kenneth Stewart
- Web page: https://patentgrep.com/patent/US8787510B2

## CPC

- H04L 25/0216: {with estimation of channel length}
- H04B 17/364: Delay profiles
- H04L 25/0228: {with direct estimation from sounding signals}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04B: TRANSMISSION

## Abstract

A method, a mobile system, and a user device for determining a delay spread are disclosed. A memory 306 may store a compound test value based on a multiburst history. The multiburst history may be a set of power delay profile decisions. A processor 304 may create a short power delay profile channel estimate and a long power delay profile channel estimate. The processor 304 may select a chosen power delay profile channel estimate based on the compound test value.

## Claims

### Claim 1

A method for determining delay spread, comprising:
storing a compound test value based on a historical multiburst set of power delay profile decisions;
receiving a new transmission burst;
creating a short power delay profile channel estimate and a long power delay profile channel estimate for the new transmission burst, wherein a delay spread of the long power delay profile channel estimate is larger than a delay spread of the short power delay profile channel estimate;
combining each of the short power delay profile channel estimate and the long power delay profile channel estimate with the compound test value based on the historical multiburst for forming a new updated compound test value; and
selecting a chosen power delay profile channel estimate from the short power delay profile channel estimate and the long power delay profile channel estimate, based on the new updated compound test value.

### Claim 2 (depends on 1)

The method of claim 1, further comprising:
correlating a training sequence code to a received signal to solve directly for the short power delay profile channel estimate.

### Claim 3 (depends on 1)

The method of claim 1, further comprising:
executing a least squares estimate on a received signal to create the long power delay profile channel estimate.

### Claim 4 (depends on 1)

The method of claim 1, further comprising:
using a first equalizer if the chosen power delay profile channel estimate is the short power delay profile channel estimate and a second equalizer if the chosen power delay profile channel estimate is the long power delay profile channel estimate.

### Claim 5 (depends on 4)

The method of claim 4, wherein the first equalizer is a least squares interference cancellation equalizer and the second equalizer is a minimum mean squared error-decision feedback equalizer.

### Claim 6 (depends on 1)

The method of claim 1, further comprising:
creating the compound test value by averaging the historical multiburst set of power delay profile decisions over a sequence of discrete-valued observations.

### Claim 7 (depends on 1)

The method of claim 1, further comprising:
observing a historical multiburst set of real-valued power delay profile observations.

### Claim 8 (depends on 1)

The method of claim 1, wherein a power delay profile decision in the historical multiburst set of power delay profile decisions is between a long test power delay profile and a short test power delay profile.

### Claim 9 (depends on 8)

The method of claim 8, wherein the long test power delay profile is a hilly terrain profile and the short test power delay profile is a typical urban profile.

### Claim 10 (depends on 1)

The method of claim 1, further including:
weighting a power delay profile decision in the historical multiburst set of power delay profile decisions.

### Claim 11

A mobile system for determining delay spread, comprising:
a memory that stores a compound test value based on a historical multiburst set of power delay profile decisions;
a processor that creates a short power delay profile channel estimate and a long power delay profile channel estimate for a new transmission burst which is received, where a delay spread of the long power delay profile channel estimate is larger than a delay spread of the short power delay profile channel estimate;
wherein the memory further stores a new updated compound test value, based upon combining each of the short power delay profile channel estimate and the long power delay profile channel estimate with the compound test value based on the historical multiburst, when a new transmission is received; and
wherein the processor further selects a chosen power delay profile channel estimate from the short power delay profile channel estimate and the long power delay profile channel estimate, based on the new updated compound test value.

### Claim 12 (depends on 11)

The mobile system of claim 11, wherein the processor creates the compound test value by averaging the historical multiburst set of power delay profile decisions over a sequence of discrete-valued set of observations.

### Claim 13 (depends on 11)

The mobile system of claim 11, wherein the processor creates the compound test value based on a historical multiburst set of real-valued power delay profile observations.

### Claim 14 (depends on 11)

The mobile system of claim 11, wherein a power delay profile decision in the historical multiburst set of power delay profile decisions is between a long test power delay profile and a short test power delay profile.

### Claim 15 (depends on 14)

The mobile system of claim 14, wherein the long test power delay profile is a hilly terrain profile and the short test power delay profile is a typical urban profile.

### Claim 16 (depends on 11)

The mobile system of claim 11, wherein weighting a power delay profile decision in the historical multiburst set of power delay profile decisions.

### Claim 17

A user device for determining delay spread, comprising:
a memory that stores a compound test value based on a multiburst history;
a processor that creates a short power delay profile channel estimate and a long power delay profile channel estimate for a new transmission burst which is received, where a delay spread of the long power delay profile channel estimate is larger than a delay spread of the short power delay profile channel estimate;
wherein the memory further stores a new updated compound test value, based upon combining each of the short power delay profile channel estimate and the long power delay profile channel estimate with the compound test value based on the historical multiburst, when a new transmission is received; and
wherein the processor further selects a chosen power delay profile channel estimate from the short power delay profile channel estimate and the long power delay profile channel estimate, based on the new updated compound test value.

### Claim 18 (depends on 17)

The user device of claim 17, wherein the processor correlates a training sequence code to a received signal to solve directly for the short power delay profile channel estimate.

### Claim 19 (depends on 17)

The user device of claim 17, wherein the processor uses a least squares computation to create the long power delay profile channel estimate.

### Claim 20 (depends on 17)

The user device of claim 17, wherein the processor creates the compound test value based on a historical multiburst set of real-valued power delay profile observations.