Patent ID: 7376172

Claim:
A transmitter for use in an orthogonal frequency division multiplexing (OFDM) based spread spectrum system, comprising: a sequence generator for generating pilot tone hopping sequences, each pilot tone hopping sequence including pilot tones, said pilot tone hopping sequences being parallel slope hopping sequences in which pilot tones in sequential pilot tone hopping sequences have parallel slopes in a time-frequency grid; a waveform generator, responsive to said pilot tone hopping sequences, for generating a waveform for transmission; wherein said sequence generator generates each of said pilot tone hopping sequences in accordance with S t ={f 0 S i , f 1 S i , . . . f k N i , . . . }, for i=1, . . . N pil ; and wherein f k S i =Z{(a(k mod T)+S t )mod p+d}, where “k” is a time instant index, “T”, “a”, “S t ,” and “d” are integer constants, “p” is a prime constant, and “Z” is a permutation operator.