# US 7,412,020 B1 · Training for time-selective wireless fading channels using cutoff rate

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- Number: US 7,412,020 B1
- Document ID: US7412020B1
- Status: Granted
- Kind: B1
- Application number: 11/166,077
- Filed: 2005-06-27
- Granted: 2008-08-12
- Earliest claimed: 2005-06-27
- Assignees: The United States of America as represented by the Secretary of the Army
- Inventors: Saswat Misra; Ananthram Swami
- Web page: https://patentgrep.com/patent/US7412020B1

## CPC

- H04L 5/003: {Arrangements for allocating sub-channels of the transmission path}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

The optimal allocation of resources—power and bandwidth—between training and data transmissions is considered for time-selective Rayleigh flat-fading channels under the cutoff rate criterion. The transmitter, assumed to have statistical channel state information (CSI) in the form of the channel Doppler spectrum, embeds known pilots symbols into the transmission stream. At the receiver, instantaneous, though imperfect, CSI is acquired through minimum mean square estimation of the channel based on some subset of pilot observations. The cutoff rate is computed and the optimal resource allocation is developed using, for example, a Gauss-Markov correlation model of a communication channel or a Jakes model.

## Claims

### Claim 1

A method of communications comprising:
determining the cutoff rate of a communication channel by analyzing an arbitrary channel correlation and a training and estimation scheme wherein the cutoff rate (RO) is determined from equation (14);
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wherein the estimation scheme is adjusted by applying the analysis of causal and noncausal estimators to the model of the communication channel; and
allocating resources for the communication channel corresponding to maximization of the cutoff rate.

### Claim 2 (depends on 1)

The method of claim 1, wherein allocating resources comprises allocating power and bandwidth of the communication channel to training symbols.

### Claim 3 (depends on 1)

The method of claim 1, wherein the communication channel is a rapidly varying channel.

### Claim 4 (depends on 1)

The method of claim 1, wherein the training and estimation scheme is Pilot Symbol Assisted Modulation (PSAM).

### Claim 5 (depends on 4)

The method of claim 4, wherein PSAM is applied to a channel correlation model of the communication channel.

### Claim 6

A system for communications comprising:
receiver adapted to sample a transmission on a communications channel;
processor adapted to determine the cutoff rate of the communication channel by analyzing an arbitrary channel correlation function and estimation scheme wherein the cutoff rate (RO) is determined from equation (14)
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and wherein the estimation scheme is adjusted by applying the analysis of causal and noncausal estimators to the model of the communication channel and;
processor adapted to allocate resources for the communication channel corresponding to maximization of the cutoff rate.

### Claim 7 (depends on 6)

The system of claim 6, wherein the processor adapted to allocate resources allocates the resources by allocating power and bandwidth of the communication channel to training symbols.

### Claim 8 (depends on 6)

The system of claim 6, wherein the communication channel is a rapidly varying fading channel.

### Claim 9 (depends on 6)

The system of claim 6, wherein the estimation scheme is Pilot Symbol Assisted Modulation (PSAM).

### Claim 10 (depends on 9)

The system of claim 9, wherein PSAM is applied to a channel correlation model of the communication channel.