| 摘要 |
Use of a training sequence having terms that are orthogonal to each other ar e employed to considerably speed up execution of the LMS algorithm. Such orthogonal sequences are developed for a channel that is described as a finite impulse response (FIR) filter having a length M new from the already existing orthogonal training sequences for at least two channels that have respective lengths M old1 and M old2 each that is less than M new such that the product of M old1 and M old2 is equal to M new when M old1 and M old2 have no common prime number factor. More specifically, a set of initial existing orthogonal training sequences is found, e.g., using those that were known in the prior art or by performing a computer search over known symbol constellations given a channe l of length M. Thereafter, an orthogonal training sequence of length M new is developed, where the product of M old1 and M old2 is equal to M new by repeating the training sequence old1 M old2 number of times to form a first concatenated sequence and repeating t he training sequence old2 M old1 number of times to form a second concatenated sequence, so that both the first concatenated sequence and the second concatenated sequence ha ve the same length. Each term of the first concatenated sequence is multiplied by the correspondingly located term in the second concatenated sequence which is placed in the same location in a new sequence made up of the resulting M new products. This new sequence is an orthogonal sequence of length M new.
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