Adapting transmit parameters in highly dynamic channel

• US 8,781,416 B1
• Filed: 09/09/2011
• Issued: 07/15/2014
• Est. Priority Date: 09/09/2011
• Status: Active Grant

• Current Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Clark, Stephen M., Cross, Ray L.
• Primary Examiner(s): Ghebretinsae, Temesgh
• Assistant Examiner(s): Chan, Richard
• Application Number:
  US13/228,993
• Time in Patent Office: 1,040 Days
• Field of Search: 455/91, 455/108, 455/114.2, 455/115.1, 455/115.3, 455/126, 455/127.1, 455/127.2
• US Class Current: 455/115.3
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/242 by comparing a transmitted test signal with a locally generated replica
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A processor determines, from signals received from other communication devices, one selected transmission mode for the communication channel conditions. The processor projects multiple channel characterization parameters in a mathematical model to each of the candidate transmission modes using a model of nominal communication channel conditions to predict whether each of the candidate transmission modes will achieve the desired communication under the nominal communication channel conditions. This results in the generation of a first subset of transmission modes. The processor also projects the multiple channel characterization parameters to each of the candidate transmission modes using a model of degraded communication channel conditions to predict whether each of the candidate transmission modes will achieve the desired communication under the degraded communication channel conditions. Such a determination results in generating a second subset of transmission modes that would successfully achieve communication. One selected transmission mode that maximizes communication objectives is selected.

Claims

1. A wireless communication device for cooperatively exchanging information with a plurality of other communication devices, comprising:

a processor configured to determine, from signals received from other communication devices, one selected transmission mode for the communication channel conditions, said determination being by;

a) obtaining multiple channel characterization parameters from signal quality parameters extracted from the available received signal properties that are being transmitted at any candidate transmission mode available to the transmitting wireless device;

b) projecting said multiple channel characterization parameters in a mathematical model to each of said candidate transmission modes using a model of nominal communication channel conditions to predict whether each of said candidate transmission modes will achieve the desired communication under said nominal communication channel conditions thus generating a first subset of transmission modes;

c) projecting said multiple channel characterization parameters in a mathematical model to each of said candidate transmission modes using a model of degraded communication channel conditions to predict whether each of said candidate transmission modes will achieve the desired communication under said degraded communication channel conditions, thus generating a second subset of transmission modes that would successfully achieve communication; and

,

d) selecting, from said first subset of transmission modes and said second subset of transmission modes, the one selected transmission mode that maximizes communication objectives while remaining stable, said selected transmission mode being obtained through the use of predetermined transmission mode selection rules that embody the communication objectives;

wherein the characterization of the communication channel does not depend on the actual transmission mode in use at the time of characterization; and

,

wherein said transmission mode selection rules to determine said one selected transmission mode from said first subset of transmission modes and said second subset of transmission modes, comprise computational implementations from one or more of the first 3 mode selection principles;

mode selection principle #1, mode selection principle #2, mode selection principle #3, being applied with cumulative effect in any numerical order followed by mode selection principle #4 followed by #5;

i) mode selection principle #1;

discard modes with unnecessarily high transmit-power—

discard any of the modes from within said first subset of transmission modes with a particular combination of transmit-power, data-rate, and modulation-type when a mode is present within said second subset of transmission modes that has the same combination of data-rate and modulation-type but having a lower transmit-power;

ii) mode selection principle #2;

discard modes with unnecessarily low data-rates—

discard modes from within said first subset of transmission modes with a particular transmit-power, data-rate, and modulation-type when a mode is present within said second subset of transmission modes, with the same transmit-power and the modulation-type but having a higher data-rate;

iii) mode selection principle #3;

discard modes with unnecessarily high bandwidths—

discard modes from within said first subset of transmission modes with a particular transmit-power, data-rate, and modulation-type when a mode is present within said second subset of transmission modes, with the same transmit-power and data-rate but having a modulation-type with a lower bandwidth;

iv) mode selection principle #4;

employ hysteresis for stability—

If after discarding modes per mode selection principle #1, mode selection principle #2, and mode selection principle #3, the set of remaining modes still contains the mode that was chosen as the selected transmission mode from the last time the evaluation was conducted, then the new selected transmission mode remains the same as the previous selected transmission mode and mode selection principle #5 is skipped; and

,

v) mode selection principle #5;

choose the best cost mode—

use a networking cost function to rank remaining modes, the lowest networking cost mode remaining in the list, after discarding modes per the mode selection principles #1, #2, #3, and #4, is chosen to be the new selected transmission mode;

the networking cost function is wireless network dependent.

2. The device of claim 1 wherein said wireless communication device determines said selected transmission mode for a plurality of other wireless communication devices that are transmitting data to said wireless communication device.

3. The device of claim 1 wherein said multiple channel characterization parameters are obtained from statistics of the differences collected between an ideal mathematical channel model and the communication channel as currently measured based on said received signal properties and local information about wireless receiver conditions.

4. The device of claim 3 wherein said multiple channel characterization parameters are derived from a group of parameters including:

the signal-to-noise ratio (SNR), signal strength, phase stability, frequency stability, message decoding success statistics, channel symbol quality statistics, and an indication of which said actual transmission mode was used to transmit the signal to a receiver of the wireless communication device.

5. The device of claim 4 wherein, said channel symbol quality statistics are computed from comparing the demodulated channel-symbols with the results of message decoding thereby producing:

a wireless-communication-channel induced channel-symbol error rate, a wireless-communication-channel induced channel-symbol erasure rate, while also taking into account said local information about wireless receiver conditions that also produce additional channel-symbol erasure rate and channel-symbol error rate that do not depend on the communication channel.

6. The device of claim 3 wherein said projecting of said multiple channel characterization parameters to said nominal communication channel conditions for said candidate transmission modes is accomplished by applying said statistics of the differences collected to said ideal mathematical channel model for each of said candidate transmission modes, with biasing and scaling operations of said statistics of the differences chosen to correspond to each of said nominal communication channel conditions for each said candidate transmission modes.

7. The device of claim 6 wherein said projecting of said multiple channel characterization parameters to said degraded communication channel conditions for said candidate transmission modes is accomplished by applying statistics of the differences collected to said ideal mathematical channel model for each of said candidate transmission modes, with said biasing and scaling operations of said statistics of the differences chosen for each of said candidate transmission modes such that results produce conditions that are degraded as compared to said nominal communication channel conditions.

8. The device of claim 6 wherein said projecting of said multiple channel characterization parameters to either said nominal communication channel conditions or said degraded communication channel conditions is accomplished by:

applying biasing and scaling operations to that portion of said multiple channel characterization parameters that have been derived primarily from said received signal properties that are different from biasing and scaling operations applied to that portion of said multiple channel characterization parameters that have been derived primarily from said local information about wireless receiver conditions.

11. The device of claim 1 wherein said degraded communication channel conditions used in determining said second subset of transmission modes used with said mode selection principle #1 are designed specifically to address the properties of said mode selection principle #1 and can be different from said degraded communication channel conditions used in determining said second subset of transmission modes used with said mode selection principle #2 are designed specifically to address the properties of said mode selection principle #2 and can be different from said degraded communication channel conditions used in determining said second subset of transmission modes used with said mode selection principle #3 which are designed specifically to address the properties of said mode selection principle #3.

12. The device of claim 1 wherein the plurality of said other wireless communication devices each determines said selected transmission mode to transmit data to said wireless communication device based on said wireless communication device conveying said received signal properties or multiple channel characterization parameters to the plurality of other wireless communication devices.

9. A wireless communication device for cooperatively exchanging information with a plurality of other communication devices, comprising:

a processor configured to determine, from signals received from other communication devices, one selected transmission mode for the communication channel conditions, said determination being by;

a) obtaining multiple channel characterization parameters from signal quality parameters extracted from the available received signal properties that are being transmitted at any candidate transmission mode available to the transmitting wireless device;

b) projecting said multiple channel characterization parameters in a mathematical model to each of said candidate transmission modes using a model of nominal communication channel conditions to predict whether each of said candidate transmission modes will achieve the desired communication under said nominal communication channel conditions thus generating a first subset of transmission modes;

c) projecting said multiple channel characterization parameters in a mathematical model to each of said candidate transmission modes using a model of degraded communication channel conditions to predict whether each of said candidate transmission modes will achieve the desired communication under said degraded communication channel conditions, thus generating a second subset of transmission modes that would successfully achieve communication; and

,

d) selecting, from said first subset of transmission modes and said second subset of transmission modes, the one selected transmission mode that maximizes communication objectives while remaining stable, said selected transmission mode being obtained through the use of predetermined transmission mode selection rules that embody the communication objectives;

wherein the characterization of the communication channel does not depend on the actual transmission mode in use at the time of characterization; and

,

wherein said nominal communication channel conditions and said degraded communication channel conditions are mathematically transformed into a set of ‘

N’

mode testing parameters wherein;

a) the number ‘

N’

can be a different number than the number of parameters contained in either said nominal communication channel conditions or said degraded communication channel conditions;

b) there is a different set of mode testing parameters for each of said candidate transmission modes for each case of said nominal communication channel conditions and said degraded communication channel conditions; and

,

c) the transformation is accomplished through a mathematical operation for which, each of the ‘

N’

mode testing parameters can depend in linear or non-linear ways on some or all of the parameters contained in either said nominal communication channel conditions or said degraded communication channel conditions.

10. The device of claim 9 wherein said prediction of whether each of said candidate transmission modes will achieve the desired communication is mathematically equivalent to determining that the point defined by said ‘

N’

mode testing parameters is contained inside of an N-dimensional region defined as a success criteria, with a different success criteria being defined for each of said candidate transmission modes with said first subset of transmission modes being determined from evaluating said mode testing parameters derived from said nominal communication channel conditions and said second subset of transmission modes being determined from evaluating said mode testing parameters derived from said degraded communication channel conditions.

13. A method for cooperatively exchanging information between a wireless communication device and a plurality of other communication devices, comprising the steps of:

a) obtaining multiple channel characterization parameters, utilizing a processor, from signal quality parameters extracted from the available received signal properties that are being transmitted at any candidate transmission mode available to the transmitting wireless device;

b) projecting said multiple channel characterization parameters in a mathematical model to each of said candidate transmission modes using a model of nominal communication channel conditions to predict whether each of said candidate transmission modes will achieve the desired communication under said nominal communication channel conditions thus generating a first subset of transmission modes;

c) projecting said multiple channel characterization parameters in a mathematical model to each of said candidate transmission modes using a model of degraded communication channel conditions to predict whether each of said candidate transmission modes will achieve the desired communication under said degraded communication channel conditions, thus generating a second subset of transmission modes that would successfully achieve communication; and

,

d) selecting, from said first subset of transmission modes and said second subset of transmission modes, the one selected transmission mode that maximizes communication objectives while remaining stable, said selected transmission mode being obtained through the use of predetermined transmission mode selection rules that embody the communication objectives;

wherein the characterization of the communication channel does not depend on the actual transmission mode in use at the time of characterization,

wherein said nominal communication channel conditions and said degraded communication channel conditions are mathematically transformed into a set of ‘

N’

mode testing parameters wherein;

a) the number ‘

N’

can be a different number than the number of parameters contained in either said nominal communication channel conditions or said degraded communication channel conditions;

b) there is a different set of mode testing parameters for each of said candidate transmission modes for each case of said nominal communication channel conditions and said degraded communication channel conditions; and

,

the transformation is accomplished through a mathematical operation for which, each of the ‘

N’

mode testing parameters can depend in linear or non-linear ways on some or all of the parameters contained in either said nominal communication channel conditions or said degraded communication channel conditions.

14. The method of claim 13 wherein said wireless communication device determines said selected transmission mode for a plurality of other wireless communication devices that are transmitting data to said wireless communication device.

15. The method of claim 13 wherein said multiple channel characterization parameters are obtained from statistics of the differences collected between an ideal mathematical channel model and the communication channel as currently measured based on said received signal properties and local information about wireless receiver conditions.

16. The method of claim 15 wherein said multiple channel characterization parameters are derived from a group of parameters including:

the signal-to-noise ratio (SNR), signal strength, phase stability, frequency stability, message decoding success statistics, channel symbol quality statistics, and an indication of which said actual transmission mode was used to transmit the signal to a receiver of the wireless communication device.

17. The method of claim 16 wherein, said channel symbol quality statistics are computed from comparing the demodulated channel-symbols with the results of message decoding thereby producing:

a wireless-communication-channel induced channel-symbol error rate, a wireless-communication-channel induced channel-symbol erasure rate, while also taking into account said local information about wireless receiver conditions that also produce additional channel-symbol erasure rate and channel-symbol error rate that do not depend on the communication channel.

18. The method of claim 15 wherein said projecting of said multiple channel characterization parameters to said nominal communication channel conditions for said candidate transmission modes is accomplished by applying said statistics of the differences collected to said ideal mathematical channel model for each of said candidate transmission modes, with biasing and scaling operations of said statistics of the differences chosen to correspond to each of said nominal communication channel conditions for each said candidate transmission modes.