Authors:
Márcio H Costa,
José C.M. Bermudez,
Neil J Bershad,
Page (NA) Paper number 1815
Abstract:
This paper presents a statistical analysis of the Least Mean Square
(LMS) algorithm when a zero-memory nonlinearity appears at the adaptive
filter output. The nonlinearity is modelled by a scaled error function.
Deterministic nonlinear recursions are derived for the mean weight
and mean square error (MSE) behavior for white gaussian inputs and
slow adaptation. Monte Carlo simulations show excellent agreement with
the behavior predicted by the theoretical models. The analytical results
show that a small nonlinear effect has a significant impact on the
converged MSE.
Authors:
Kazushi Ikeda,
Hideaki Sakai,
Page (NA) Paper number 1275
Abstract:
The normalized LMS (N-LMS) algorithm has a disadvantage that the convergence
rate is much worse when the input signal is colored. To overcome this,
the affine projection algorithm and the block orthogonal projection
(BOP) algorithm which are applied the block signal processing technique
to the N-LMS algorithm are proposed although the reason why they are
tough against the coloredness is not given yet. This paper gives the
convergence rate of the BOP algorithm for colored input signals, which
shows the superiority of the BOP algorithm. To put it concretely, we
derive the expression of the convergence rate, propose an approximation
method to calculate it, and confirm the result by computer simulations.
We also consider the relation between the block size and the convergence
rate formally and geometrically.
Authors:
Hichem Besbes,
Yousra Ben Jemaa,
Meriem Jaidane,
Page (NA) Paper number 1441
Abstract:
The affine projection algorithm (APA)is a very promising algorithm
that has good convergence properties when the input signal is correlated.
In particular, it's used to perform communications systems: echo cancellation,
equalization...However, due to its complexity, there is no available
transient and steady state analysis. In this paper, we present an exact
analysis approach tailored for digital transmission context. In such
context, the input signal remains in a finite alphabet set. With a
discrete Markov chain model of the inputs, we can describe accurately
the APA's behavior without any unrealistic assumption. In particular
we can calculate the exact value of the critical and optimum step size.
Moreover, we provide the exact Mean Square Deviation for all step size
and input correlation. The influence of high order statistics can be
enhanced.
Authors:
Roberto López-Valcarce,
Soura Dasgupta,
Page (NA) Paper number 1766
Abstract:
This work provides conditions on the input sequence that ensure the
exponential asymptotic stability of the inverse of the forward prediction
error filter obtained by means of the Recursive Weighted Least Squares
algorithm. Note that this filter is in general time varying. Thus this
result is a natural extension to the well-known minimum phase property
of forward prediction error filters obtained by the autocorrelation
method.
Authors:
Mahesh Godavarti,
Alfred O Hero III,
Page (NA) Paper number 1775
Abstract:
Partial Updating of LMS filter coefficients is an effective method
for reducing the computational load and the power consumption in adaptive
filter implementations. Only in the recent past has any work been done
on deriving conditions for filter stability, convergence rate, and
steady state error for the Partial Update LMS algorithm. In [5] approximate
bounds were derived on the step size parameter mu which ensure stability
in-the-mean of the alternating even/odd index coefficient updating
strategy. Unfortunately, due to the restrictiveness of the assumptions,
these bounds are unreliable when fast convergence (large mu) is desired.
In this paper, tighter bounds on mu are derived which guarantee convergence
in-the-mean of the coefficient sequence for the case of wide sense
stationary signals.
Authors:
Kaywan H Afkhamie, Communications Research Laboratory, McMaster University, Hamilton, Ontario, Canada L8S 4K1 (Canada)
Zhi-Quan Luo, Communications Research Laboratory, McMaster University, Hamilton, Ontario, Canada L8S 4k1 (Canada)
Page (NA) Paper number 1998
Abstract:
Interior Point Optimization techniques have recently emerged as a new
tool for developing parameter estimation algorithms. These algorithms
aim to take advantage of the fast convergence properties of interior
point methods, to yield, in particular, fast transient performance.
In this paper we develop a simple "analytic center" based algorithm,
which updates estimates with a constant number of computation (independent
of number of samples). The convergence analysis shows that the asymptotic
performance of this algorithm matches that of the well-known least
squares filter (provided some mild conditions are satisfied). Some
numerical simulations are provided to demonstrate the fast transient
performance of the interior point algorithm.
Authors:
Robert A. Soni,
Kyle A. Gallivan,
W. Kenneth Jenkins,
Page (NA) Paper number 2402
Abstract:
Reliable performance is very important for high speed channel equalizers
and echo cancellers used in high speed communications channels. A common
type of hardware fault occurs when the coefficients get ``stuck'' at
an uncontrollable value. Such faults lead to larger overall mean square
errors, and generally poor performance. Redundancy can provide the
ability to compensate for these types of faults if the proper design
is introduced into the adaptive filter structure. Unfortunately, this
form of redundancy can lead to poor convergence performance for the
adaptive filter after the fault occurrence. This paper examines the
use of affine projection and row projection techniques to improve
the convergence performance of the fault tolerant adaptive filtering
structure. Algorithms are developed for two cases: fault knowledge
and no fault knowledge incorporated in the adaptive filtering update.
These algorithms are introduced in this paper and simulations are presented
to illustrate the effectiveness of these approaches.
Authors:
Shue-Lee Chang,
Tokunbo Ogunfunmi,
Page (NA) Paper number 2423
Abstract:
This paper presents a detailed performance analysis of third-order
nonlinear adaptive systems based on the Wiener model. In earlier work,
we proposed the discrete Wiener model for adaptive filtering applications
for any order. However, we had focused mainly on first and second-order
nonlinear systems in our previous analysis. Now, we present new results
on the analysis of third and higher-order systems. This results can
be extended to higher-oder systems. The Wiener model has many advantages
over other models such as the Volterra model. These advantages include
less number of coefficients and faster convergence. The Wiener model
performs a complete orthogonalization procedure to the truncated Volterra
series and this allows us to use linear adaptive filtering algorithms
like the LMS to calculate all the coefficients efficiently. Unlike
the Gram-Schmidt procedure, this orthogonalization method is based
on the nonlinear discrete Wiener model. It contains three sections.
It contains three sections: a single-input multi-output linear with
memory section, a multi-input, multi-output nonlinear no-memory section
and a multi-input, single-output amplification and summary section.
Computer simulation results are also presented to verify the theoretical
performance analysis results.
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