US 5,504,783 A · Frequency diversity transmitter and receiver

Abstract

A frequency diversity communication system is provided whereby the number of hopping channels is reduced and a more continuous communication achieved as a mobile station travels from cell to cell by the combination of chips of symbols from the mobile sources. The transmitter divides each symbol of an input symbol sequence into a number K of chips, which are modulated with mutually different carrier frequencies. The receiver demodulates the signal sent by the transmitter by local frequencies corresponding respectively to the K different carrier frequencies. According to this invention, the carrier phase is coherent for each frequency of the received wave. Moreover, because the carrier phase is coherent, the outputs for each frequency of the received wave can be combined with the use of a training signal. The receiver also performs an estimation of the maximum likelihood of the transmitted symbol to eliminate the need for decoding. It is also provided that the order of the chips of the symbols is rearranged within a burst.

Claims31

Dependent claims

A frequency diversity communication system comprising:

a transmitter unit, comprising:
splitting means for splitting each symbol of an input symbol sequence into a plurality K of chips;
carrier frequency generating means for generating a plurality K of mutually differing frequencies as carrier frequencies, said carrier frequencies having a preset initial phase;
chip modulation means for modulating said chips with said carrier frequencies;
chip transmitting means for transmitting said modulated chips;
and
a first receiver unit receiving a signal transmitted from said transmitting unit, said first receiver unit comprising:
local frequency generating means for generating said plurality K of said mutually differing frequencies as local frequencies, each of said local frequencies being substantially in phase with an initial phase of a respective one of said carrier frequencies;
and
demodulation means for demodulating an input to said first receiver with said local frequencies.

7 more elements

A frequency diversity receiver unit for receiving signals comprising:

local frequency generating means for generating a plurality K of mutually differing frequencies as local frequencies, each of said local frequencies being substantially in phase with an initial phase of a respective one of carrier frequencies;
demodulation means for demodulating an input to said receiver with said local frequencies;
combining means responsive to said demodulation means for combining a plurality K of chips into an individual symbol of an input symbol sequence;
quasi-coherent detection means for extracting a plurality K of complex envelope signals from said received signal using an output of said local frequency generating means;
and
decision means for determining a transmitted symbol from said complex envelope signals.

3 more elements

Dependencies are inferred from the claim text.

Frequency diversity transmitter and receiver

Life of this patent

Frequency diversity transmitter and receiver

Life of this patent

Abstract

Claims31