Orthogonal frequency division multiplexing/modulation communication system for improving ability of data transmission and method thereof
First Claim
1. A system for improving error correction capability in an OFDM (Orthogonal Frequency Division Multiplexing) communication system, comprising:
- a Reed-Solomon encoder for coding input information data, and outputting a Reed-Solomon block comprised of a second number of Reed-Solomon symbols each comprised of a first number of Reed-Solomon symbol elements; and
an interleaver for receiving the Reed-Solomon block, and dispersing the Reed-Solomon symbol elements existing in a specified one Reed-Solomon symbol within the received Reed-Solomon block in the same sub-channel positions in a fourth number of sub-channels of each of a third number of consecutive OFDM symbols.
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Accused Products
Abstract
Disclosed is an OFDM communication system and method for improving frequency utilization efficiency. In the system, a Reed-Solomon encoder codes input information data, and outputs a Reed-Solomon block comprised of a second number of Reed-Solomon symbols each comprised of a first number of Reed-Solomon symbol elements. An interleaver receives the Reed-Solomon block, and disperses the Reed-Solomon symbol elements existing in a specified one Reed-Solomon symbol within the received Reed-Solomon block in the same sub-channel positions in a fourth number of sub-channels of each of a third number of consecutive OFDM symbols.
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Citations
32 Claims
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1. A system for improving error correction capability in an OFDM (Orthogonal Frequency Division Multiplexing) communication system, comprising:
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a Reed-Solomon encoder for coding input information data, and outputting a Reed-Solomon block comprised of a second number of Reed-Solomon symbols each comprised of a first number of Reed-Solomon symbol elements; and
an interleaver for receiving the Reed-Solomon block, and dispersing the Reed-Solomon symbol elements existing in a specified one Reed-Solomon symbol within the received Reed-Solomon block in the same sub-channel positions in a fourth number of sub-channels of each of a third number of consecutive OFDM symbols. - View Dependent Claims (2, 3)
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4. A system for repeatedly transmitting sub-channels in an OFDM communication system, comprising:
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a sub-channel repeater for repeating input data blocks so as to transmit each of the input data blocks over a predetermined number of sub-channels; and
a plurality of mappers for mapping the sub-channels output from the sub-channel repeater according to a predetermined modulation mode. - View Dependent Claims (5, 6, 7, 8)
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9. A system for performing sub-channel assignment in an OFDM communication system, comprising:
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a plurality of selectors for selecting a specific sub-channel data block among input sub-channel data blocks according to a control signal, and transmitting the selected sub-channel data block over a corresponding sub-channel; and
a sub-channel assignment controller for controlling sub-channel assignment such that each of the selectors converts a sub-channel data block to be selected from the sub-channel data blocks in a predetermined period of time. - View Dependent Claims (10)
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11. A system for transmitting sub-channels having a minimum PAPR (Peak-to-Average Power Ratio) in on OFDM communication system, comprising:
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a pilot scrambling code generator for generating a predetermined number of pilot scrambling codes for identifying pilot sub-channel data blocks among input sub-channel data blocks;
a scrambling code generator for generating a predetermined number of scrambling codes for scrambling the input sub-channel data blocks;
a plurality of first multipliers for multiplying the input pilot sub-channel data blocks by a first pilot scrambling code among the pilot scrambling codes, for scrambling;
a plurality of second multipliers for multiplying the sub-channel data blocks excluding the pilot sub-channel data blocks from the input sub-channel data blocks and data blocks output from the first multipliers by a first scrambling code among the scrambling codes, for scrambling;
a first inverse fast Fourier transformer (IFFT) for IFFT-transforming the signals output from the second multipliers;
a plurality of third multipliers for multiplying the input pilot sub-channel data blocks by a second pilot scrambling code among the pilot scrambling codes, for scrambling;
a plurality of fourth multipliers for multiplying the sub-channel data blocks excluding the pilot sub-channel data blocks from the input sub-channel data blocks and data blocks output from the third multipliers by a second scrambling code among the scrambling codes, for scrambling;
a second IFFT for IFFT-transforming the signals output from the fourth multipliers;
first and second PAPR calculators for calculating PAPRs of the sub-channel data blocks output from the first IFFT and the second IFFT, respectively; and
a selector for selecting sub-channel data blocks output from the first and second IFFTs having a minimum PAPR among the calculated PAPRs, and transmitting the selected sub-channel data blocks over a sub-channel of the OFDM communication system. - View Dependent Claims (12, 13, 14, 15, 19, 20)
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16. A system for receiving sub-channels having a minimum PAPR in an OFDM communication system, comprising:
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a pilot extractor for extracting pilot sub-channel data blocks among input sub-channel data blocks;
a scrambling code generator for generating a plurality of scrambling codes for scrambling the input sub-channel data blocks;
a pilot scrambling code extractor for extracting received pilot scrambling codes by descrambling the input sub-channel data blocks with the scrambling codes;
a plurality of first multipliers for multiplying the extracted pilot sub-channel data blocks by complex-conjugated values of the extracted pilot scrambling codes;
a pilot scrambling code generator for generating a predetermined number of pilot scrambling codes, the number of generated pilot scrambling codes being equal to the number of pilot scrambling codes transmitted by a transmitting system;
a plurality of second multipliers for multiplying conjugated values of the generated pilot scrambling codes by the values output from the first multipliers;
a scrambling code extractor for extracting scrambling codes by multiplying the data blocks output from the second multipliers by the pilot sub-channel data blocks transmitted by the transmission system; and
a demodulator for demodulating the received sub-channel data blocks by scrambling the received sub-channel data blocks with the extracted scrambling codes.
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17. A transmission system employing transmission antenna diversity in an OFDM communication system, comprising:
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a first antenna for transmitting an in-phase signal having no phase offset with output data, upon receiving the output data; and
a second antenna for alternately transmitting the received output data as an in-phase signal having no phase offset with the output data and as a phase-inversed signal having a 180°
-phase offset with the output data in a training symbol period.
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18. A method for improving error correction capability in an OFDM (Orthogonal Frequency Division Multiplexing) communication system, comprising the steps of:
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coding input information data, and outputting a Reed-Solomon block comprised of a second number of Reed-Solomon symbols each comprised of a first number of Reed-Solomon symbol elements; and
performing interleaving by dispersing the Reed-Solomon symbol elements existing in a specified one Reed-Solomon symbol within the received Reed-Solomon block in the same sub-channel positions in a fourth number of sub-channels of each of a third number of consecutive OFDM symbols.
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21. A method for repeatedly transmitting sub-channels in an OFDM communication system, comprising the steps of:
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repeating input data blocks so as to transmit each of the input data blocks over a predetermined number of sub-channels; and
mapping the sub-channels over which the input data blocks are repeated, according to a predetermined modulation mode. - View Dependent Claims (22, 23, 25, 27, 28, 29)
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24. A method for performing sub-channel assignment in an OFDM communication system, comprising the steps of:
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transmitting input sub-channel data blocks over corresponding sub-channels connected at an initial input point; and
transmitting input sub-channel data blocks received after a lapse of a predetermined time from the initial input point, over sub-channels different from the sub-channels connected at the initial input point.
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26. A method for transmitting sub-channels having a minimum PAPR (Peak-to-Average Power Ratio) in on OFDM communication system, comprising the steps of:
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(a) generating a predetermined number of pilot scrambling codes for identifying pilot sub-channel data blocks among input sub-channel data blocks, and generating a predetermined number of scrambling codes for scrambling the input sub-channel data blocks;
(b) multiplying the input pilot sub-channel data blocks by a first pilot scrambling code among the pilot scrambling codes, for scrambling;
(c) multiplying the sub-channel data blocks excluding the pilot sub-channel data blocks from the input sub-channel data blocks and pilot sub-channel data blocks scrambled with the first pilot scrambling code by a first scrambling code among the scrambling codes, for scrambling;
(d) IFFT-transforming the signals generated in the step (c);
(e) multiplying the input pilot sub-channel data blocks by a second pilot scrambling code among the pilot scrambling codes, for scrambling;
(f) multiplying the sub-channel data blocks excluding the pilot sub-channel data blocks from the input sub-channel data blocks and data blocks output in the step (b) by a second scrambling code among the scrambling codes, for scrambling;
(g) IFFT-transforming the signals generated in the step (f); and
(h) calculating PAPRs of the sub-channel data blocks generated in the steps (d) and (g), respectively, selecting sub-channel data blocks having a minimum PAPR among the calculated PAPRs, and transmitting the selected sub-channel data blocks over a sub-channel of the OFDM communication system.
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30. A method for receiving sub-channels having a minimum PAPR in an OFDM communication system, comprising the steps of:
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(a) extracting pilot sub-channel data blocks among input sub-channel data blocks;
(b) generating a plurality of scrambling codes for scrambling the input sub-channel data blocks, and extracting received pilot scrambling codes by descrambling the input sub-channel data blocks with the scrambling codes;
(c) multiplying the extracted pilot sub-channel data blocks by complex-conjugated values of the extracted pilot scrambling codes;
(d) generating a predetermined number of pilot scrambling codes, the number of generated pilot scrambling codes being equal to the number of pilot scrambling codes transmitted by a transmitting system, and multiplying conjugated values of the generated pilot scrambling codes by the values generated in the step (c); and
(e) extracting scrambling codes by multiplying the data blocks generated in the step (d) by the pilot sub-channel data blocks transmitted by the transmission system, and demodulating the received sub-channel data blocks by scrambling the received sub-channel data blocks with the extracted scrambling codes.
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31. A transmission method employing transmission antenna diversity in an OFDM communication system, comprising the steps of:
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transmitting an in-phase signal having no phase offset with output data, upon receiving the output data of the OFDM communication system; and
alternately transmitting the received output data as an in-phase signal having no phase offset with the output data and as a phase-inversed signal having a 180°
-phase offset with the output data in a training symbol period.
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32. An OFDM communication system comprising:
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a Reed-Solomon interleaver for dispersing Reed-Solomon symbol elements existing in the same positions, obtained by Reed-Solomon coding input information data blocks, to sub-channels of the OFDM symbols, for interleaving;
a sub-channel repeater for converting the interleaved singles to parallel data blocks, repeating the parallel data blocks a predetermined number of times, and transmitting the repeated data blocks over corresponding sub-channels;
a sub-channel assignor for adding the sub-channel data blocks and the pilot sub-channel data blocks, and dynamically assigning sub-channels for transmitting the sub-channel data blocks each time the added sub-channel data blocks are received, according to input time points;
a sub-channel scrambler for mapping the assigned sub-channel signals according to a predetermined modulation mode, scrambling pilot sub-channel data blocks among the mapped sub-channel data blocks with a pilot scrambling code, and scrambling the scrambled pilot sub-channel data blocks and the remaining mapped sub-channel data blocks with the scrambling code;
a selector for IFFT-transforming a signal output from the sub-channel scrambler, and selecting sub-channel data blocks having a minimum PAPR among the IFFT-transformed sub-channel data blocks; and
antennas for transmitting the sub-channel data blocks output from the selector as an in-phase signal having no phase offset, and alternately transmitting the sub-channel data blocks output from the selector as an in-phase signal having no phase offset and a phase-inversed signal having a 180°
-phase offset in a training symbol period.
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Specification