Method and apparatus for selection of ARQ parameters and estimation of improved communications

• US 20040193972A1
• Filed: 04/05/2004
• Published: 09/30/2004
• Est. Priority Date: 05/17/2001
• Status: Active Grant

• Current Assignee: Valtrus Innovations Limited (f/k/a Dolya Holdco 9 Limited) (Key Patent Innovations Limited)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Mitlin, Vlad, Mueller, A. Joseph
• Granted Patent: US 7,137,047 B2
• Time in Patent Office: Days
• US Class Current: 714/704
• CPC Class Codes: H03M 13/353 Adaptation to the channel
• CPC Class Codes: H03M 13/6306 Error control coding in combination with Automatic Repeat reQuest [ARQ] and diversity transmission, e.g. coding schemes for the multiple transmission of the same information or the transmission of incremental redundancy H03M13/3761, H03M13/3769 and H03M13/635 take precedence
• CPC Class Codes: H03M 13/6337 Error control coding in combination with channel estimation
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/1816 with retransmission of the same, encoded, message
• CPC Class Codes: H04L 1/1825 Adaptation of specific ARQ protocol parameters according to transmission conditions
• CPC Class Codes: H04L 1/203 Details of error rate determination, e.g. BER, FER or WER
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems

Abstract

The present invention includes a method for selecting appropriate forward error correction and automatic repeat request parameters for protection of a multicarrier communication channel. The multicarrier communication channel may be wired or wireless. Particular aspects of the present invention are described in the claims, specification and drawings.

Claims

1. A method of approximating a bit error rate applicable to a multicarrier communications channel, including:

measuring an average signal to noise ratio across effective subcarriers of the channel; and

analytically approximating a bit error rate from at least the average signal to noise ratio, an average bit loading of the effective subcarriers, and forward error correction and automatic repeat request parameters.

2. A method of approximating a signal to noise ratio gain resulting from application of an automatic repeat request protocol with a particular maximum number of transmissions allowed, to a forward error correction encoded multicarrier communications channel, including:

measuring an initial average signal to noise ratio across the effective subcarriers of the channel; and

analytically approximating a signal to noise ratio gain from at least the initial average signal to noise ratio, an average bit loading of the effective subcarriers, forward error correction parameters and a parameter for the particular maximum number of transmissions allowed.

3. A method of selecting communication parameters to be applied to a multicarrier communications channel, including:

measuring an initial signal to noise ratio across effective subcarriers of the channel;

accessing previously recorded analytical approximations of one or more bit error rates resulting from application of one or more communication parameters to a range of signal to noise ratios including the measured initial signal to noise ratio, wherein the previously recorded analytical approximations derived from;

selecting a range of signal to noise ratios applicable to the effective subcarriers of the channel;

selecting a set of alternative communication parameters describing an average bit loading of the subcarriers and forward error correction and automatic repeat request handling; and

analytically approximating a bit error rate for the range of SNRs and the set of alternative communication parameters; and

selecting the communication parameters to be applied based at least in part on the measured initial signal to noise ratio and the previously recorded analytical approximations.

4. The method of claim 3, wherein the approximations are recorded as splines.

5. The method of claim 3, wherein the approximations are recorded as interpolation tables.

6. A method of selecting communication parameters to be applied to a multicarrier communications channel, including:

measuring an initial signal to noise ratio across effective subcarriers of the channel;

accessing previously recorded analytical approximations of one or more signal to noise ratio gains resulting from application of one or more communication parameters to a range of signal to noise ratios including the measured initial signal to noise ratio, wherein the previously recorded analytical approximations derived from analytically approximating a signal to noise ratio gain from at least an initial signal to noise ratio, an average bit loading of the effective subcarriers, forward error correction parameters and a parameter for the particular maximum number of transmissions allowed; and

selecting the communication parameters to be applied based at least in part on the previously recorded analytical approximations.

7. The method of claim 6, wherein the approximations are recorded as splines.

8. The method of claim 6, wherein the approximations are recorded as interpolation tables.

9. A method of selecting forward error correction parameters for use in a communications session having multiple communications channels, including the steps:

measuring an average signal to noise ratio of effective subcarriers of the channel and counting the effective subchannels to be loaded with data; and

selecting from stored communication parameters associated with predicted net signal to noise ratio gains for the communication parameters, wherein the predicted net signal to noise ratio gains were previously derived at least for pairs of forward error correction parameters S and R/S across a range of average signal to noise ratios and a range of number of effective subcarriers to be loaded with data bits, wherein S is the number of symbol sets per codeword and R/S is a number redundancy symbols per codeword divided by S.

10. The method of claim 9, wherein the predicted net signal to noise ratio gains are recorded as splines.

11. The method of claim 9, wherein the predicted net signal to noise ratio gains are recorded as interpolation tables indexed by the measured initial signal to noise ratio and a count of the effective subcarriers.