Communications system and method for multi-carrier orthogonal coding

A communication system and coding technology, applied in the field of communication systems and methods of multi-carrier orthogonal coding, capable of solving problems such as result interference

Inactive Publication Date: 2002-09-25
TELEFON AB LM ERICSSON (PUBL)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the delayed echoes of one code received due to multipath propagation are usually not orthogonal to other undelayed codes, resulting in undesired interference

Method used

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  • Communications system and method for multi-carrier orthogonal coding
  • Communications system and method for multi-carrier orthogonal coding
  • Communications system and method for multi-carrier orthogonal coding

Examples

Experimental program
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Embodiment Construction

[0030] best practice

[0031]In FIG. 1, which has been partially described previously, the spread-spectrum coded signals Ia, Qa; Ib, Qb; . . . ; middle. Each spread-coded signal is illustrated as a pair of signals I, Q which represent the real and imaginary parts of the signal waveform after spread-coding. The signals Ia, Qa; Ib, Qb; . . . ; In, Qn can be a sequence of digital samples or a continuous waveform that has been filtered by a smoothing filter (not shown). A combiner 24 forms a weighted sum of the I (real part) signal and a weighted sum of the Q (imaginary part) signal to obtain a composite I, Q signal Itot, Qtot which is applied to the modulator together with a desired channel frequency signal 28 26 in order to generate the modulated signal 30. A linear power amplifier 32 is caused to amplify the modulated signal 30 to a desired transmit power level and then transmit it via an antenna 34 . The fraction of the total transmit power allocated to each signal is cont...

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Abstract

In CDMA systems, a message to be transmitted is redundantly coded for transmission using a combination of error-correction coding and a spread-spectrum access code. The coded message is modulated to a first radio frequency channel, or band, and also to at least one other frequency channel, which may be either an adjacent or a non-adjacent channel. Other messages for transmission are generated likewise and the signals for transmission on the first channel are summed using a set of weighting factors, with the weighted sum transmitted on the first channel. The same signals are summed for transmission on the at least one other frequency channel, but using weighting factors that have a progressive relative phase rotation compared to their values on the first channel. The sequence of weighting factors used for one signal across the different frequency channels is preferably orthogonal to the sequence of weighting factors used for a different signal.

Description

[0001] Cross References to Related Applications [0002] This application is U.S. Patent Application No. 08 / 898,392, filed July 22, 1997 by Dent, entitled "Communication System and Method with Orthogonal Block Encoding," and filed by Dent in 1998. A follow-up to 09 / 082,722, filed May 21, entitled "Partially Block-Interleaved CDMA Coding and Decoding," both applications are pending. field of invention [0003] The present invention is directed to spread spectrum wireless communication systems that transmit messages with a large number of redundant codes to provide for distinguishing one signal from overlapping signals and, more particularly, to an improved method for encoding messages on more than one channel. Cross-coding techniques, for example, when a message is spread over more than one frequency channel in a multi-carrier CDMA (Code Division Multiple Access) system. Background of the invention [0004] Figure 1 illustrates a prior art quadrature transmitter, shown gener...

Claims

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Application Information

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IPC IPC(8): H04J1/00H04B1/69H04B1/707H04L1/00H04L5/02
CPCH04B1/692H04B1/707H04B1/712H04J13/00H04L1/004H04L5/0019
InventorP·W·登特
OwnerTELEFON AB LM ERICSSON (PUBL)