Method and communication system device for the generation or processing of OFDM symbols in a transmission system with spread user data

• US 7,738,571 B2
• Filed: 09/16/2002
• Issued: 06/15/2010
• Est. Priority Date: 09/18/2001
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Haas, Harald, Costa, Elena, Rohling, Hermann, Schulz, Egon, Galda, Dirk
• Primary Examiner(s): Vo; Don N
• Application Number:
  US10/489,956
• Publication Number:
  US 20050018782A1
• Time in Patent Office: 2,829 Days
• Field of Search: 375/260, 375/299
• US Class Current: 375/260
• CPC Class Codes: H04L 27/2636 with FFT or DFT modulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] transmitter or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]
• CPC Class Codes: H04L 5/026 using code division

Abstract

OFDM symbols are generated using data from one or more users or from one or more data sources represented on a number of sub-carriers. To inhibit multiple-access interference on application of the CDMA principle, the data are transformed in a data-source specific manner and only subsequently allocated to the sub-carriers, independently of the transformation.

Claims

1. A method for creating orthogonal frequency division multiplex symbols in a signal broadcast by a communication system, comprising:

in a first operation of the communication system, obtaining data values by applying a Fourier transform to data from a data source, and mapping the data values obtained to orthogonal subcarriers of a carrier;

in a second operation of the communication system, mapping the data values to a group of blocks, each of the blocks including all of the data values, where the number of blocks depends on the number of orthogonal subcarriers used; and

in a third operation of the communication system, producing one of the orthogonal frequency division multiplex symbols by adding a guard interval to the group of blocks to produce an output signal that is physically different from the data from the data source.

2. A method in accordance with claim 1, wherein data extracted from the one of the orthogonal frequency division multiplex symbols is used upon receipt by repetition of a complete data sequence corresponding to a number of assigned subcarriers and a subsequent frequency shift.

3. A method in accordance with claim 1, wherein said obtaining of the data values maps transformed data from one of the data sources to a number of the orthogonal subcarriers and only the transformed data of one data source is assigned to each orthogonal subcarrier.

4. A method in accordance with claim 3, wherein the transformed data of each of the data sources is distributed evenly over the carrier.

5. The method of claim 1, further comprising processing the data from the data source by applying channel coding and modulation prior to the first operation.

6. A device in a communication system, comprising:

a data input unit receiving data from at least one data source;

at least one storage unit, coupled to said data input unit, temporarily storing the data from the at least one data source; and

a control device, coupled to said at least one storage unit, obtaining data values by applying a Fourier transform to the data received by said data input unit, mapping the data values obtained to orthogonal subcarriers of a carrier, then mapping the data values to a group of blocks, each of the blocks including all of the data values, where the number of blocks depends on the number of orthogonal subcarriers used, and producing one of the orthogonal frequency division multiplex symbols by adding a guard interval to the group of blocks.

7. A mobile station in a communication system, generating orthogonal frequency division multiplex symbols, comprising:

a data input unit receiving data from at least one data source;

at least one storage unit, coupled to said data input unit, temporarily storing the data from the at least one data source; and

a control device, coupled to said at least one storage unit, generating the orthogonal frequency division multiplex symbols by repeating symbols and producing a frequency shift of the orthogonal frequency division multiplex symbols, corresponding to conversion of serial into parallel data, subscriber-specific Fourier Transformation, mapping onto subcarriers, inverse Fourier Transformation and conversion of parallel into serial data.