Method for configuring data and energy parameters in a multi-channel communications system
First Claim
1. A method of configuring sub-channels of a high speed multi-channel transmission system, which system is intended to transmit data at a data rate R using N sub-channels, said method comprising the steps of:
- (a) determining K signal-to-noise values associated with K sub-channels, where K≦
N; and
(b) determining data capacities of each of the K sub-channels based on an evaluation of the following parameters;
i) the K signal-to-noise values; and
ii) said data rate R; and
iii) a number Nch of the K sub-channels having a non-zero bit capacity; and
wherein the data capacities are determined in one or more iterations of step (b) and Nch is re-calculated during each iteration.
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Abstract
A process for optimizing the bit and energy configurations of data sub-channels in a multi-channel data transmission signal is disclosed. The inventive process is preferably embodied in an microcode routine executable by a high speed digital signal processor. The routine monitors, analyzes and stores sub-channel signal-to-noise characteristics, determines theoretical bit capacity loadings, evaluates power performance margins, and optimizes sub-channel configurations based on a series of iterative calculations intended to maximize the overall system power performance margin for any given target data rate. Alternatively, for a given power performance margin, the achieved data rate can be maximized. To achieve these results, a number of non-zero bit sub-channels (NCH) are remembered from iteration to iteration, which results in a more optimal loading of the sub-channels. A unique new approach is also disclosed for deciding which of the sub-channels should be disabled to have a zero bit loading. If adjustments to bit loadings are required to achieve a particular initial target rate, those sub-channels which will have the least effect on the overall system performance margin are adjusted first, so that compliance with system performance margin requirements is better achieved. In addition, an "iteration criteria" count can be incorporated in the process to ensure that the initialization of sub-channel loadings can be effectuated (at least to a very close order) in a predetermined and controlled fashion. The resulting bit/energy loadings can be adjusted to be fully compliant with applicable Discrete Multi-Tone (DMT) implementations of Asymmetric Digital Subscriber Loop (ADSL) protocols.
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Citations
53 Claims
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1. A method of configuring sub-channels of a high speed multi-channel transmission system, which system is intended to transmit data at a data rate R using N sub-channels, said method comprising the steps of:
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(a) determining K signal-to-noise values associated with K sub-channels, where K≦
N; and(b) determining data capacities of each of the K sub-channels based on an evaluation of the following parameters; i) the K signal-to-noise values; and ii) said data rate R; and iii) a number Nch of the K sub-channels having a non-zero bit capacity; and wherein the data capacities are determined in one or more iterations of step (b) and Nch is re-calculated during each iteration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of configuring sub-channel parameters of a high speed multi-channel transmission system, which system is intended to transmit data at a target rate R using K sub-channels, said method comprising the steps of:
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(a) determining K signal-to-noise values associated with K sub-channels, where K≦
N; and(b) determining optimal data capacities for each of the K sub-channels based on an evaluation of the following parameters; i) the K signal-to-noise values; and ii) said target rate R; and iii) an iteration criteria count M; and wherein the optimal data capacities are determined in M or fewer iterations of step (b). - View Dependent Claims (21, 22, 23, 24, 25, 26)
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27. A method of configuring sub-channel parameters in a high speed multi-channel transmission system, which system is intended to transmit data at a target data rate R using K sub-channels, said method comprising the steps of:
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(a) determining signal to noise values associated with some or all of said sub-channels; and (b) executing a set of computations in one or more iterations to determine appropriate bit loadings for said sub-channels; and wherein during each iteration of step (b) a sub-channel usability determination is made of which of the K sub-channels should be disabled, such determination being based on a consideration of a calculated minimum (bmin) and maximum (bmax) bit capacity of said sub-channels; and further wherein during each iteration of step (b) bit loadings are made only for sub-channels which are not disabled during such iteration. - View Dependent Claims (28, 29, 30, 31)
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32. A method of configuring a high speed transmission system to achieve a data rate R using K sub-channels and with an overall target output power value P, said method comprising the steps of:
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(a) determining signal to noise values associated with some or all of said sub-channels; and (b) calculating a proposed minimum (bmin) and a proposed maximum (bmax) bit loading for the data capacities of sub-channels that are not disabled; and (c) calculating an output power value P'"'"' associated with such proposed loading; and (d) if P'"'"'>
P, removing bit capacity in sorted order from those sub-channels which have the greatest differential in power requirements between loadings in which they carry bmin or bmax ; andwherein bit capacity is removed until P'"'"' is substantially equal to P; and (e) calculating a proposed data rate R'"'"' based on the results of steps (b)-(d). - View Dependent Claims (33, 34, 35, 36)
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37. A method of maximizing a data rate Btotal in a high speed multi-channel transmission system, which system is intended to transmit data using K sub-channels, and constrained to use a total transmission power P, and a power margin γ
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m, said method comprising the steps of;
(a) determining signal-to-noise associated with some or all of said sub-channels; and (b) determining which of the K sub-channels should be disabled; (c) determining a proposed minimum (bmin) and a proposed maximum (bmax) bit loading for the data capacities of sub-channels that are not disabled; and (d) determining an output power value P'"'"' and power modification factors, emax and emin associated with such proposed bit loadings; and (e) replacing bmax with bmin, and emax with emin, for one or more sub-channels, until P'"'"' ≦
P;whereby Btotal =Σ
bmax for all the sub-channels, and is maximized for such values of P and γ
m. - View Dependent Claims (38, 39, 40, 41, 42, 43)
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m, said method comprising the steps of;
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44. A method of maximizing a power performance margin γ
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m in a high speed multi-channel transmission system, which system is intended to transmit data using K sub-channels and a target rate Btarget, said method comprising the steps of;
(a) determining signal-to-noise associated with some or all of said sub-channels; and (b) determining which of the K sub-channels should be disabled; (c) determining a proposed bit loading for the data capacities of sub-channels that are not disabled based on a nominal power performance margin γ
m ; and(d) calculating a difference Δ
B=Btotal -Btarget, where Btotal is an achieved data rate based on the proposed bit loading; and(e) calculating a new nominal power performance margin γ
'"'"'m based on Δ
B; and(f) replacing γ
m with γ
'"'"'m and repeating steps (b) through (e) as necessary until Δ
B=0;wherein γ
m is maximized for said target rate Btarget. - View Dependent Claims (45, 46)
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m in a high speed multi-channel transmission system, which system is intended to transmit data using K sub-channels and a target rate Btarget, said method comprising the steps of;
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47. A method of implementing an adaptive procedure for configuring a high speed transmission system using K sub-channels which system can be set to either a first mode achieving a maximum data rate, or a second mode achieving a maximum power performance margin, said method comprising the steps of:
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(a) determining signal-to-noise values associated with some or all of said sub-channels; and (b) determining which of the K sub-channels should be disabled; and (c) determining a proposed bit loading for the data capacities of sub-channels that are not disabled based on a nominal power performance margin γ
m ; and(d) when said first mode is selected, setting said system to use a maximum data rate which is based on the results of step (c) and thereafter terminating said adaptive procedure; and (e) when said second mode is selected, calculating a difference Δ
B=Btotal -Btarget, where Btotal is an achieved rate based on the proposed bit loading, and Btarget is a target rate for said system; and(f) calculating a new nominal performance margin γ
'"'"'m based on Δ
B; and(g) replacing γ
m with γ
'"'"'m and repeating steps (b), (c), (e) and (f) as necessary until Δ
B=0 thereby maximizing γ
m for the given value of Btarget and thereafter terminating said adaptive procedure. - View Dependent Claims (48, 49, 50)
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51. A method of configuring a high speed multi-channel transmission system, which system is intended to transmit data using K sub-channels, said method comprising the steps of:
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(a) determining signal-to-noise values associated with some or all of said sub-channels; and (b) determining a proposed minimum (bmin) and a proposed maximum (bmax) bit loading for the data capacities of sub-channels; and (c) determining power modification factors, emax and emin associated with such proposed bit loadings; and (d) disabling deficient sub-channel by evaluating bmax, bmin, emax and emin ; and (e) loading only non-disabled sub-channels with data; wherein said system is configured only to use non-disabled sub-channels for data transmissions. - View Dependent Claims (52, 53)
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Specification