Gradient Of Mean Square Error Research Articles

Gradient-based variable forgetting factor RLS algorithm in time-varying environments

In this paper, a new control mechanism for the variable forgetting factor (VFF) of the recursive least square (RLS) adaptive algorithm is presented. The control algorithm is basically a gradient-based method of which the gradient is derived from an improved mean square error analysis of RLS. The new mean square error analysis exploits the correlation of the inverse of the correlation matrix with itself that yields improved theoretical results, especially in the transient and steady-state mean square error. It is shown that the theoretical analysis is close to simulation results for different forgetting factors and different model orders. The analysis yields a dynamic equation of mean square error that can be used to derive a dynamic equation of the gradient of mean square error to control the forgetting factor. The dynamic equation can produce a positive gradient when the error is large and a negative gradient when the error is in the steady state. Compared with other variable forgetting factor algorithms, the new control algorithm gives fast tracking and small mean square model error for different signal-to-noise ratios (SNRs).

Gradient based variable forgetting factor RLS algorithm

An accurate new variable forgetting factor recursive least-square adaptive algorithm is derived. An improved mean square behaviour analysis is presented, which shows that the theoretical analysis and the simulation results are close to each other. The control of the forgetting factor is based on the dynamic equation of the gradient of mean square error. Compared with other variable forgetting factor algorithms, the new algorithm provides fast tracking and small mean square model error, and its performance will not be degraded much even in low signal-to-noise ratios.

Variable forgetting factor RLS algorithm based on dynamic equation of gradient of mean square error

A new variable forgetting factor RLS adaptive algorithm is introduced. The control of the forgetting factor is based on the dynamic equation of the gradient of the mean square error. Compared with other algorithms, the new algorithm gives fast tracking. Has a small mean square model error, and is insensitive to SNR.