Communication system and method with orthogonal block encoding

Abstract

A communication system and method with orthogonal, block encoding is provided. Encoded signals are transmitted by repeating transmissions of symbol blocks with a phase or sign change selected for each block from a sequence of phase or sign changes. Different symbols are transmitted using orthogonal sequences. The decoding uses different orthogonal sequences for separating the received encoded signals into corresponding separate channels. The orthogonal encoding is removed from the encoded transmitted signals and corresponding ones of the repeated symbols are added in successively received repeated blocks after the orthogonal encoding is removed. A transmitter uses a digital source encoder to encode information into symbols, and each symbol is repeated a preselected number of times to successively produce groups of repeated bits. Each repeat bit is changed in phase or sing by application of a sign or phase change determined by a selected assigned orthogonal code associated with the transmitter. The sign changed bits are interleaved from a number of such groups to successively generate a number of blocks, each composed of the different sign or phase changed bits of the preselected number of repeated groups and having a collective sign or phase change corresponding to a common sign change or phase shared by all bits of the block. The interleaved blocks then modulate a radio signal for transmission.

Description

Background of the invention [0001] Generally speaking, the present invention relates to a communication system and method for encoding transmitted signals, and in particular, relates to an orthogonal communication method using orthogonal encoding technology. [0002] The frequency band is consciously extended by using redundant coding, since doing so will bring benefits to the performance parameters. But these benefits are lost if the communication channel has delayed echoes, time dispersion, or multipath effects. [0003] Code Division Multiple Access CDMA is a well-known technique for artificially spreading the transmit band. CDMA is an extension of the well-known redundant coding technique, eg it repeats the transmission and uses a majority vote in the receiver to combine the repeated signals. In some CDMA, also called direct-sequence spread spectrum applications, a mixture of simple repetition, or "dumb spreading," and error-correcting coding, or "smart spreading," is us...

AI Technical Summary

Problems solved by technology

The need for guard time between slots reduces the bandwidth capacity of the system, and the use of an equalizer does not completely eliminate the effects of multipath propagation

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