Abstract: Provided is a method of generating an orthogonal set in a quasi-synchronous spread spectrum system, the method including selecting a two-level autocorrelation sequence at a sequence selector, selecting a first indices set and a second indices set from the two-level autocorrelation sequence, and generating two quasi-orthogonal sets using the first indices set and the second indices set, at an orthogonal code generator.

Abstract: A method of per-tone spreading in single carrier block transmissions, includes generating a block of modulated symbols, and performing the per-tone spreading on the block of the modulated symbols. Also, a transmitter configured to perform per-tone spreading in single carrier block transmissions, includes a modulator configured to generate a block of modulated symbols, and a spreader configured to perform the per-tone spreading on the block of the modulated symbols.

Abstract: A method of generating a pair of orthogonal sets with a spreading factor N for a direct sequence spread spectrum communication system, includes selecting a two-level autocorrelation sequence of a period of N?1, the two-level autocorrelation sequence including elements, each of which includes a value of 1 or 0, and obtaining binary sequences based on the two-level autocorrelation sequence. The method further includes obtaining quasi-orthogonal sets based on the two-level autocorrelation sequence and the binary sequences, and generating the pair of the orthogonal sets based on the quasi-orthogonal sets.

Abstract: A method of timing synchronization in sub-band based ultra wideband systems, includes obtaining a coarse estimate of an offset in a time domain at a sub-sampled rate, and obtaining a fine estimate of the offset in an analog domain. The method further includes correcting a timing in the analog domain by transforming the fine estimate to an equivalent phase for the correcting.

Abstract: A method of a transmitter, includes multiplying a data sequence by a first code, and multiplying a training sequence by a second code that is orthogonal to the first code. The method further includes adding the multiplied data and training sequences, and transmitting, to a receiver, the added data and training sequences.

Abstract: A method of generating a pair of orthogonal sets with a spreading factor N for a direct sequence spread spectrum communication system, includes selecting a two-level autocorrelation sequence of a period of N?1, the two-level autocorrelation sequence including elements, each of which includes a value of 1 or 0, and obtaining binary sequences based on the two-level autocorrelation sequence. The method further includes obtaining quasi-orthogonal sets based on the two-level autocorrelation sequence and the binary sequences, and generating the pair of the orthogonal sets based on the quasi-orthogonal sets.