MT-CDMA using spreading codes with interference-free windows

A non-interference, spreading code technology applied in the field of digital transmission, which can solve the problems of high peak-to-average power ratio, loss of user capacity, system frequency offset and nonlinear amplification sensitivity, etc.

Inactive Publication Date: 2005-08-31
KONINK PHILIPS ELECTRONICS NV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] OFDM technology has various drawbacks: synchronization is difficult to perform, and the system is sensitive to frequency offset and nonlinear amplification, which results in high peak-to-average power ratio (PAPR)
However, this advantage is achieved at the cost of increased inter-carrier interference (ICI), which negates this advantage, and thus the increase in user capacity may be lost

Method used

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  • MT-CDMA using spreading codes with interference-free windows
  • MT-CDMA using spreading codes with interference-free windows
  • MT-CDMA using spreading codes with interference-free windows

Examples

Experimental program
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Embodiment Construction

[0019] figure 1 One MT-CDMA transmitter is shown. The MT-CDMA scheme is mainly proposed for uplink communication of cellular systems due to its asynchronous structure. The encoder ENCOD encodes the input data symbols S of any user k into coded data symbols Sc. The serial-to-parallel converter S / P converts the input coded data symbols Sc into Nc low-rate parallel sub-streams, each of which modulates the subcarrier f p (p=0,...Nc-1), and are added up to obtain one OFDM symbol. The duration Ts of the input encoded data symbols is increased by a factor Nc to obtain T=Nc*Ts as the OFDM symbol duration at the output of the adder. This OFDM symbol is then spread with the associated waveform C of user k k (t) is expanded and sent.

[0020] figure 2 shows the spectrum of the MT-CDMA signal, including the f 0 , f 1 ,.., f Nc-1 Nc subcarriers of . The subcarrier spacing is 1 / T, so the Nc parallel data substreams satisfy the requirement of orthogonality before expansion. Howev...

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Abstract

The invention relates to digital transmission. It particularly relates to a method of transmitting data using multi-carrier Code-division Multiple Access (CDMA) for accessing a transmission system. The method comprises a step of modulating the data to be transmitted using Orthogonal Frequency-division Multiplexing (OFDM) for producing OFDM modulated data symbols and a step of spreading the OFDM modulated data symbols with spreading codes including a set of predefined sequences, wherein the sequences are predefined so that they satisfy predetermined auto-correlation and / or cross-correlation criteria within a region around the zero-time offset of the correlation function, defined as an interference Free Window (IFW).

Description

technical field [0001] The present invention generally relates to digital transmission. In particular, the present invention relates to a method of transmitting data using multi-carrier Code Division Multiple Access (CDMA) to access a transmission system and a method of receiving such transmitted data. [0002] The invention also relates to a system, a transmitter and a receiver for implementing the above method. [0003] The invention also relates to a computer program product for implementing such a method. [0004] The invention is especially suitable for the future generation of high data rate mobile communication systems (higher than the third generation). Background technique [0005] Due to the ever-increasing demand for high-speed mobile data communications, partly due to the expectation that multimedia services will surpass voice services in the near future, next-generation cellular wireless systems, also known as 4G systems, face challenges in providing high-capa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04J1/00H04B1/707H04J13/00H04L5/02
CPCH04L5/026H04B2201/709709H04J13/00H04B1/707H04J11/0023H04L27/2627
Inventor A·布拉亚尔B·于纳尔塞拉克L·劳尔C·莫利埃
Owner KONINK PHILIPS ELECTRONICS NV
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