Consider an LEO constellation of
N satellite nodes connected through a time-varying Inter-Satellite Link (ISL) graph. At each time step
t, the aggregated nodal traffic
displays coupled periodicity at two scales: the orbital period
and the diurnal cycle [
8]. Multiscale temporal mixing [
34] can handle such nonstationarity; yet point predictors trained under MSE converge to the conditional mean and thereby attenuate heavy-tailed peaks.
3.1. Dual Branch Backbone and Temporal Decomposition
We decompose the observed traffic into three components through a cascaded dual-scale EMA scheme. Let denote the historical traffic series at a given node, where is the feature dimension and is the lookback window.
Building on prior single-scale decomposition designs, our approach further exploits the a priori knowledge that LEO traffic is simultaneously governed by two distinct physical periods: the diurnal cycle
min, fixed by Earth’s rotation, and the orbital period
specific to each constellation, obtained from Systems Tool Kit (STK) orbital propagation. The cascaded decomposition takes the following form:
The smoothing factors are tied directly to the physical periods instead of being treated as free hyperparameters. Following the standard EMA window–smoothing relation:
where
is the sampling interval. For
min and a medium-scale constellation of 298 satellites at 1015 km altitude with
min, one obtains
and
. Here, the diurnal trend
captures the slowly evolving ground demand pattern; the orbital component
isolates the periodic oscillation induced by coverage changes; and the residual
represents the heavy-tailed bursty traffic that is most responsible for SLA violations. With
, the diurnal branch effectively operates as a low pass filter that spans multiple revolutions and tracks baseline drift at the day scale, while the rapid dynamics driven by coverage are absorbed by
and the burst residual.
Given this decomposition, an Interleaved Dual Branch Backbone processes both scales in parallel. The orbital and burst residuals
,
are concatenated, segmented into patches of fixed length, and encoded through a lightweight convolutional stream, while the diurnal trend
passes through a linear projection. Although the two branches share an identical architecture, they maintain independent parameters, and each branch outputs a discrete probability distribution over a distinct support set—
or
. To keep computation per node manageable when many service classes share the same satellite, the backbone adopts a Strategy with Independent Channels: each traffic feature is treated as a univariate input, thereby avoiding the quadratic cost that cross-channel attention would incur [
8].
In this study, we follow the established direct multi-step prediction paradigm, abbreviated as Non-Iterative Direct Mapping (NDM), to circumvent autoregressive error accumulation over long horizons. Let
and
collect the respective lookback windows for the diurnal and residual streams. Each future step
h is predicted by a dedicated decoder head that outputs a probability vector over the support set specific to its branch,
or
:
where
is the decoder head for step
h within the structure with independent channels and
assigns probability mass to each bin of
; the staggered branch
, corresponding to the
intervals of
, is obtained with an identical architecture but independent parameters. By predicting each horizon step directly, the formulation avoids error accumulation.
3.2. Spectral Penalty
Neural networks trained with objectives defined solely in the time domain develop an inherent spectral bias toward low-frequency components during gradient descent. Because the burst residual concentrates the transient energy that drives SLA violations, this bias is most harmful in the high-frequency band where severe traffic spikes reside.
To counter this effect, we incorporate a regularizer in the frequency domain termed Spectral Penalty, drawing on recent loss designs in the frequency domain [
35]. Let
denote the one-dimensional Discrete Fourier Transform (DFT). The penalty measures how much the spectral amplitudes of the predicted and true dynamic components diverge, up to the Nyquist frequency:
where
extracts the spectral magnitude. In order to structurally preserve the high-frequency energy associated with severe transient bursts during training, the deterministic sequence
fed to the DFT is extracted through a differentiable Soft Argmax operation over the discrete support set centroids. Gradients from
thus flow through the probability-weighted centroid of the predicted distribution. The DFT coefficient at frequency
for a sequence
is
Note that the summation in
starts from
, which excludes the zero-frequency component. Normalization by
keeps the penalty invariant to the prediction horizon length. Because
retains near-zero mean after the cascaded EMA subtraction and the zero-frequency bin is already excluded from
, the dominant source of spectral leakage is suppressed and no additional windowing is applied.
is defined on amplitude-spectrum discrepancies of the burst component and enters the total training loss in Equation (
8) through a weighting coefficient
. The spectral term is not intended to serve as the sole timing constraint, because the stepwise negative log-likelihood is computed in the original time domain and penalizes temporally misaligned burst predictions. Thus, the amplitude-spectrum penalty complements the time-domain distributional loss by preserving burst-related high-frequency energy, while temporal localization remains anchored by the time-domain objective.
3.3. Quantization and Distributional Fusion
To approximate the continuous conditional distribution with a categorical output, the traffic domain must be mapped to a finite set of bins. Because uniform binning offers poor resolution in the tails, we construct a Nonuniform Support Set from the inverse CDF of the training traffic distribution.
Let M denote the number of intervals, delimited by boundary points . These boundaries are chosen so that , meaning every bin carries equal probability mass, an arrangement known as equiprobable quantization. The primary support set is then .
Both the inverse CDF and the resulting bin boundaries are computed exclusively from the training split, which prevents data leakage. Because traffic statistics vary with orbital latitude and service class, the bins are not shared globally; instead, each satellite calibrates its own support sets and independently for each node and class, accommodating spatial heterogeneity without any centralized recalibration step.
Whenever the true traffic value falls near a bin boundary , probability mass can leak to adjacent bins, distorting the reconstructed expectation.
To mitigate this boundary effect explicitly, we introduce a second staggered support set
whose boundaries are offset to the midpoints of the primary bins:
These
M midpoints delimit
staggered intervals, giving
. By staggering the bins in this way, the worst-case discretization error at bin edges is reduced, and the combined system can approximate continuous distributions with a moderate number of bins, as illustrated in
Figure 3.
The complete training objective combines the Negative Log-Likelihood (NLL) with the spectral regularizer:
where
is chosen by grid search on the validation set.
Outputs from the two interleaved branches are fused to construct an empirical CDF,
. The two branch distributions are not collapsed to a single expectation; instead, each node computes a cumulative sum weighted by confidence over both branch probability masses. Let
and
be the softmax-normalized probability vectors for the primary and staggered support sets, respectively. The fusion weight
is defined as the normalized peak probability of the primary branch:
, which gives a larger weight to whichever branch is sharper, i.e., more confident. The fused empirical CDF evaluated at traffic volume
y is then
where
and
identify the ordinal indices of the support set bins containing
y.
To extract closed-form moments, the centroids of all
and
bins are collected into a sorted union. Each centroid inherits a probability mass weighted by branch confidence:
The predictive expectation and variance then follow as
where
is the centroid of bin
m and
is the fused probability mass. In this formulation,
serves as the point forecast for capacity sizing, while
quantifies the intrinsic predictive uncertainty. The risk-aware allocation mechanism described in
Section 4 uses its square root
as an endogenous risk index for each service class. Because the allocator recomputes these moments every
, meaning that the scheduling interval matches the forecasting sampling interval, each resource allocation decision is conditioned on the most recent distributional output.
The practical value of conditioning allocation decisions on the most recent distributional output lies in the paired estimates that it provides for each service class: near-term demand and predictive uncertainty. The demand estimate represents the nominal load expected during the next scheduling interval, while the standard deviation summarizes the short-term variability associated with bursty and heavy-tailed arrivals. This distinction matters in LEO satellite nodes because traffic surges can increase shared onboard-buffer pressure before delayed control signals clearly reveal congestion. Feeding the paired forecast to the allocator allows bandwidth margins to reflect both expected load and traffic fluctuation, easing resource-allocation pressure under constrained onboard capacity.