Saswat Panigrahi

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Dynamic spectrum management (DSM) is an effective technique for mitigating detrimental effect of crosstalk in digital subscriber lines (DSL). Among various DSM techniques, centralized optimal spectrum balancing (OSB) achieves the maximum possible data rates by computing the optimal power spectral densities (PSDs) for all modems in DSL systems.(More)
This paper presents efficient multiuser margin optimization algorithms suitable for multicarrier digital subscriber line (DSL) systems using Dynamic Spectrum Management (DSM). The favorable monotonicity and fairness properties of multiuser margin are employed to formulate a box-constrained nonlinear least squares (NLSQ) problem for multiuser margin(More)
While most existing loading algorithms for xDSL-DMT systems strive for the optimal energy distribution to maximize their rate, the amounts of bits loaded to subcarriers are constrained to be integers and the associated granularity losses can represent a significant percentage of the achievable data rate, especially in the presence of the peak-power(More)
This paper proposes a centralized optimum spectrum management (OSM) technique with group power constraint (GPC), which jointly determines total transmission power and power spectral densities (PSD) of the different lines to control the crosstalks in a fully collaborative manner for digital subscriber lines (DSL) systems. Dual decomposition is employed to(More)
This paper proposes a low-complexity selective iterative water-filling (SIW) algorithm that can considerably enhance the performance of IW. Unlike the highly complicated and centralized OSM, the SIW has a complexity of at most N times that of IW algorithm and is quasi-autonomous requiring very little centralized coordination. Simulation results in realistic(More)
Multiuser margin maximization algorithms are developed for multi-carrier Digital Subscriber Loops (DSL) employing Dynamic Spectrum Management (DSM). Margin maximization is desirable for constant bit rate applications and provides protection against various non-stationary and bursty noise sources. Most single-user margin maximization algorithms rely on a(More)
Bit-rounding algorithms are practically attractive because they are relatively computationally efficient and implementationally realizable because they ensure integer-bit distribution. However, due to the concave nature of the rate-energy relationship these algorithms often tend to load bits aggressively, which leads to the system BER constraint violation.(More)
In this paper, we present a multi-user resource allocation technique for multi-carrier digital subscriber loop (DSL) systems using an adaptive coding/modulation scheme. Traditional bit loading based on only adaptive modulation requires the number of bits to be integer and hence causes granularity loss that can be significant in dynamic spectrum management(More)
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