Apparatus for transmitting and receiving signal using orthogonal codes and non-binary values in CDMA/OFDM system and method thereof

• US 7,215,635 B2
• Filed: 12/27/2002
• Issued: 05/08/2007
• Est. Priority Date: 10/30/2002
• Status: Active Grant

• Current Assignee: Uniloc 2017 LLC (SoftBank Group Corp.)
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Song, Seog-Ill, Kong, Hyung-Yun, Oh, Hyun-Seo
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): Jagannathan, Melanie
• Application Number:
  US10/330,800
• Publication Number:
  US 20040085919A1
• Time in Patent Office: 1,593 Days
• Field of Search: None
• US Class Current: 370/208
• CPC Class Codes: H04B 2201/709709 Methods of preventing interference
• CPC Class Codes: H04J 11/003 at the transmitter transmission to multiple receive units in multiple input multiple output [MIMO] H04B7/0452; transmit antenna weighting H04B7/0615
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04L 25/022 of frequency response
• CPC Class Codes: H04L 25/0222 Estimation of channel variability, e.g. coherence bandwidth, coherence time, fading frequency
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 27/206 using a pair of orthogonal carriers, e.g. quadrature carriers
• CPC Class Codes: H04L 27/2605 Symbol extensions, e.g. Zero Tail, Unique Word [UW]
• CPC Class Codes: H04L 27/2634 Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 27/36 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 5/0016 Time-frequency-code
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority

Abstract

An apparatus for transmitting and receiving a signal in Code Division Multiple Access/Orthogonal Frequency Division Multiplexing (CDMA/OFDM) system is provided. The apparatus discriminates user signals with a unique spreading code and the orthogonal codes, increases data transmission rate with the non-binary value without increasing of entire bandwidth used by the users, solves signal interference with interleaver and diversity effect of interleaving and OFDM, and maximizes transmission efficiency by varying modulation schemes depending on channel states.

Claims

1. A transmitting apparatus of Code Division Multiple Access/Orthogonal Frequency Division Muliplexing (CDMA/OFDM) comprising:

first serial/parallel converting means for performing serial-to-parallel conversion for received external data to be transmitted;

mapping means for generating non-binary signals from parallel data converted at the first serial/parallel converting means;

temporally orthogonal coding (TOC) means for converting the non-binary signals generated at the mapping means to data having orthogonality;

unique spreading code synthesizing means for spreading the data having orthogonality converted at the temporally orthogonal coding means by multiplying with a unique spreading code;

second serial/parallel converting means for performing serial-to-parallel conversion for the data spread at the unique spreading code synthesizing means;

complex Inverse Fast Fourier Transform (IFFT) means for performing IFFT for parallel data converted at the second serial/parallel converting means;

parallel/serial converting and guard interval inserting means for performing serial-to-parallel conversion and inserting guard interval for the data IFFTed at the complex IFFT means;

modulating means for modulating the data received from the parallel/serial converting and guard interval inserting means multiplying with a Radio Frequency (RF); and

synthesizing means for synthesizing the data modulated at the modulating means to transmit to the air.

2. The transmitting apparatus as recited in claim 1, further comprising interleaving means for interleaving the spread parallel data received from the second serial/parallel converting means to output to the complex IFFT means.

3. The transmitting apparatus as recited in claim 1, further comprising adaptive modulation controlling means for estimating channel state by using data from a receiving apparatus and controlling the IFFT means and the parallel/serial converting and guard inserting means based on the estimated channel state.

4. The transmitting apparatus as recited in claim 3, the adaptive modulation controlling means includes:

channel state estimating means for receiving FFTed data for a received signal from the receiving apparatus, computing signal to noise ratio (SNR) of sub-channels of the transmitted data, and estimating channel state by using the SNR;

system state checking processing means for checking system state due to system load of the transmitting apparatus itself;

timely optimizing processing means for computing mean and variance for variation of the SNR computed at the channel state estimating means and computing time mean of the system state checked at the system state checking processing means;

adaptive modulation selection processing means for performing adaptive modulation by controlling the mapping means and the complex IFFT means based on the channel state and the system state by using the output data of the timely optimizing processing means; and

sub-channel selection processing means for adjusting assignment of sub-carriers by controlling the mapping means and the serial/parallel converting and guard interval inserting means based on the channel state and the system state by using the output data of the timely optimizing processing means.

5. The transmitting apparatus as recited in one of claim 1 to 4, wherein the temporally orthogonal coding (TOC) means includes:

third serial/parallel converting means for performing serial-to-parallel conversion for the non-binary signal generated by the mapping means;

orthogonal code multiplying means for multiplying the parallel data converted at the third serial/parallel converting means with a predetermined number of orthogonal codes, respectively; and

signal synthesizing means for synthesizing the data outputted from the orthogonal code multiplying means.

6. A receiving apparatus of Code Division Multiple Access/Orthogonal Frequency Division Muliplexing (CDMA/OFDM) comprising:

demodulating means for demodulating a signal transmitted from a transmitting apparatus by multiplying with an external RF;

low pass filtering means for passing low frequency component of the analog signal demodulated at the demodulating means;

analog/digital converting and guard interval inserting discarding means for converting the analog signal filtered by the low pass filtering means to digital data and discarding the guard interval from the converted digital data;

complex Fast Fourier Transform (FFT) means for performing complex FFT for the output data of the analog/digital converting and guard interval inserting discarding means;

first parallel/serial converting means for converting the parallel data from the complex FFT means to serial data;

unique spreading code synthesizing means for de-spreading the serial data converted at the first parallel/serial converting means by multiplying with a unique spreading code;

de-temporally orthogonal coding (de-TOC) means for converting the orthogonal data from the unique spreading code synthesizing means to non-binary signals having no orthogonality;

de-mapping means for recovering binary data from the non-binary signals from the de-temporally orthogonal coding means; and

serial/parallel converting means for performing serial/parallel conversion for the data recovered by the de-mapping means.

7. The receiving apparatus as recited in claim 6, further comprising de-interleaving means for de-interleaving the FFTed data from the complex FFT means to output to the first parallel/serial converting means.

8. The receiving apparatus as recited in claim 6 or 7, wherein the de-temporally orthogonal coding means includes:

orthogonal code multiplying means for multiplying the parallel data de-spread at the unique spreading code synthesizing means with a predetermined number of orthogonal codes, respectively;

integrating means for integrating the outputs of the orthogonal code multiplying means, respectively, to recover transmitted data; and

second parallel/serial converting means for converting the parallel data recovered at the integrating means to serial data.

9. A transmitting method for use in a transmitting apparatus of Code Division Multiple Access/Orthogonal Frequency Division Muliplexing (CDMA/OFDM) comprising the steps of:

(a) at first serial/parallel converting means, performing serial-to-parallel conversion for external data to be transmitted and, at mapping means, generating non-binary signals from the converted parallel data;

(b) at temporally orthogonal coding (TOC) means, converting the generated non-binary signal to data having orthogonality;

(c) at unique spreading code synthesizing means, spreading the converted orthogonal data by multiplying with a unique spreading code and, at second serial/parallel converting means, performing serial-to-parallel conversion for the spread data;

(d) at complex Inverse Fast Fourier Transform (IFFT) means, performing IFFT for the parallel data converted at the step (c);

(e) at parallel/serial converting and guard interval inserting means, performing serial-to-parallel conversion for the IFFTed data and inserting guard interval; and

(f) at modulating means, modulating the guard interval inserted data by multiplying with an external RF and, at synthesizing means, synthesizing the modulated data to transmit to the air.

10. The transmitting method as recited in claim 9, further comprising the step (g) of, at interleaving means, interleaving the parallel data of the step (c), prior to performing complex IFFT at the step (d).

11. The transmitting method as recited in claim 9, further comprises the step (h) of, at adaptive modulating means, estimating channel state by using data from a receiving apparatus and controlling the mapping means of the step (a), the complex IFFT means of the step (d) and the parallel/serial converting and guard interval inserting means of the step (e) based on the estimated channel state.

12. The transmitting method as recited in claim 11, wherein the step (h) includes the steps of:

(i) at channel state estimating means, receiving FFTed data for a received signal from the receiving apparatus, computing signal to noise ratio (SNR) of sub-channels of the transmitted data, and estimating channel state by using the SNR;

(j) at system state checking processing means, checking system state due to system load of the transmitting apparatus itself;

(k) at timely optimizing processing means, computing mean and variance for variation of the SNR computed at the step (i) and computing time mean of the system state checked at the step (j);

(l) at adaptive modulation selection processing means, performing adaptive modulation by controlling the mapping means and the complex IFFT means of the step (d) based on the channel state and the system state by using the output data of the timely optimizing processing means of the step (k); and

(m) at sub-channel selection processing means, adjusting assignment of sub-carriers by controlling the mapping means of the step (a) and the serial/parallel converting and guard interval inserting means of the step (e) based on the channel state and the system state by using the output data of the timely optimizing processing means of the step (k).

13. The transmitting method as recited in one of claim 9 to 12, wherein the step (b) includes:

(n) at third serial/parallel converting means, performing serial-to-parallel conversion for the non-binary signal generated by the mapping means at the step (b);

(o) at orthogonal code multiplying means, multiplying parallel data converted at the step (n) with a predetermined number of orthogonal codes, respectively; and

(p) at signal synthesizing means, synthesizing the data outputted from the orthogonal code multiplying means of the step (o).

14. A receiving method for use in a receiving apparatus of Code Division Multiple Access/Orthogonal Frequency Division Multiplexing (CDMA/OFDM) comprising the steps of:

(a) at demodulating means, demodulating a signal transmitted from a transmitting apparatus by multiplying with an external RF and, at low pass filtering means, passing low frequency component of the demodulated analog signal;

(b) at analog/digital converting and guard interval inserting discarding means, converting the analog signal filtered in the step (a) by the low pass filtering means to digital data and discarding the guard interval from the converted digital data;

(c) at complex FFT means, performing complex FFT for the output data of the analog/digital converting and guard interval inserting discarding means;

(d) at first parallel/serial converting means, converting the parallel data from the complex FFT means to serial data and, at unique spreading code synthesizing means, de-spreading the serial data converted at the first parallel/serial converting means by multiplying with a unique spreading code;

(e) at de-temporally orthogonal coding (de-TOC) means, converting the orthogonal data from the unique spreading code synthesizing means of the step (d) to non-binary signals having no orthogonality; and

(f) at de-mapping means, recovering binary data from the non-binary signals from the de-temporally orthogonal coding means and, at serial/parallel converting means, performing serial-to-parallel conversion for the data recovered by the de-mapping means.

15. The receiving method as recited in claim 14, further comprising the step (q) of, at de-interleaving means, de-interleaving data that is complex FFTed at the step (c).

16. The receiving method as recited in claim 14 or 15, wherein the step (e) includes the steps of:

(h) at orthogonal code multiplying means, multiplying the parallel data de-spread at the step (d) with a predetermined number of orthogonal codes, respectively;

(i) at integrating means, integrating the outputs of the orthogonal code multiplying means at the step (h), respectively, to recover transmitted data; and

(j) at second parallel/serial converting means, converting the recovered parallel data to serial data.

17. A computer readable recording medium embodied therein a program for implementing, in a transmitting apparatus of CDMA/OFDM having a processor, for transmission using orthogonal code and non-binary signal value, the functions of:

(a) at first serial/parallel converting means, performing serial-to-parallel conversion for external data to be transmitted and generating, at mapping means, non-binary signals from the converted parallel data;

(b) at temporarily orthogonal coding (TOC) means, converting the generated non-binary signal to data having orthogonality;

(c) at unique spreading code synthesizing means, spreading the converted orthogonal data by multiplying with a unique spreading code and, at second serial/parallel converting means, performing serial-to-parallel conversion for the spread data;

(d) at complex IFFT means, performing IFFT for the parallel data converted in the function (c);

(e) at parallel/serial converting and guard interval inserting means, performing serial-to-parallel conversion, for the IFFTed data and inserting guard interval; and

(f) at modulating means, modulating the guard interval inserted data by multiplying with an external RF and, at synthesizing means, synthesizing the modulated data to transmit to the air.

18. The computer readable recording medium as recited in claim 17, wherein the program further implements the function (g) of, at interleaving means, interleaving the parallel data in the function (c), prior to performing complex IFFT of the function (d).

19. The computer readable recording medium as recited in claim 17 or 18, the program further implements the function (h) of, at adaptive modulating means, estimating channel state by using data from a receiving apparatus and controlling the mapping means of the function (a), the complex IFFT means of the function (d) and the parallel/serial converting and guard interval inserting means of the function (e) based on the estimated channel state.

20. A computer readable recording medium having embodied therein a program for implementing in a receiving apparatus of Code Division Multiple Access/Orthogonal Frequency Division Multiplexing (CDMA/OFDM) having a processor, a method for receiving a signal using orthogonal code and non-binary signal value, the method comprising:

(a) at demodulating means, demodulating a signal transmitted from a transmitting apparatus by multiplying with an external RF and, at low pass filtering means, passing low frequency component of the demodulated analog signal;

(b) at analog/digital converting and guard interval inserting discarding means, converting the analog signal filtered in the function (a) by the low pass filtering means to digital data and discarding the guard interval from the converted digital data;

(c) at complex FFT means, performing complex FFT for the output data of the analog/digital converting and guard interval inserting discarding means;

(d) at first parallel/serial converting means, converting the parallel data from the complex FFT means to serial data and, at unique spreading code synthesizing means, de-spreading the serial data converted at the first parallel/serial converting means by multiplying with a unique spreading code;

(e) at d e-temporally orthogonal coding (de-TOC) means, converting the orthogonal data from the unique spreading code synthesizing means of the function (d) to non-binary signals having no orthogonality; and

(f) at de-mapping means, recovering binary data from the non-binary signals from the de-temporally orthogonal coding means and, at serial/parallel converting means, performing serial/parallel conversion for the data recovered by the de-mapping means.

21. The computer readable recording medium as recited in claim 20, the program further implements the function (g) of, at de-interleaving means, de-interleaving data that is complex FFTed in the function (c).