Transmission and receiving using spreading modulation for spread spectrum communications and thereof apparatus

• US 7,215,656 B1
• Filed: 11/30/2000
• Issued: 05/08/2007
• Est. Priority Date: 12/04/1999
• Status: Expired due to Fees

• Current Assignee: Korea Advanced Institute of Science and Technology
• Original Assignee: Korea Advanced Institute of Science and Technology
• Inventors: Park, Su Won, Sung, Dan Keun, Kim, Jong Myeong
• Primary Examiner(s): Pham; Chi
• Assistant Examiner(s): JONES, PRENELL P
• Application Number:
  US09/890,249
• Time in Patent Office: 2,350 Days
• Field of Search: 370/336, 370/317, 370/335, 370/342, 370/328, 370/508, 370/519, 370/503, 370/324, 370/320, 370/332, 370206-210, 370/280, 375/146, 375/130, 375/295, 375/296, 375/346, 375141-144, 375/285, 375/219, 375/150, 375/148, 375/149, 375/325, 375/371, 455/434, 348/663, 348/668, 348/659, 348/665, 348/667
• US Class Current: 370/336
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes

Abstract

The present invention is related to a method and an apparatus for the orthogonal complex-domain spreading modulation in CDMA spread spectrum communication system when there are channels with statistically higher transmitting power. In CDMA spread spectrum communication systems with a transmitter and a receiver, the transmitter according to the invention has several channels with different information. Two channels with higher power than the others, which are spread in the conventional scheme, are spread with the orthogonal codes using a complex-domain multiplier. The spread signals are added. Then the signals are scrambled using a complex-domain multiplier with secondary scrambling sequences generated by a special scrambling code generator with primary scrambling sequences as inputs. The receiver does reverse operation of the transmitter.

Claims

1. A transmitting method in CDMA (Code Division Multiple Access) systems with a transmitting apparatus and receiving apparatus, comprising the steps of:

(a) generating a pilot signal and transmitting data signals for several channels with different information, said data signals including a pair of data signals and additional data signals;

(b) supplying a pair of the data signals to a complex multiplier and spreading the pair of the data signals with complex orthogonal codes to obtain complex valued first spread signals, and spreading the additional data signals with complex orthogonal codes to obtain second spread signals;

(c) adding the first complex valued spread and the second signals;

(d) scrambling the added complex valued signals using complex valued PN (Pseudo-Noise) sequences;

(e) modulating the scrambled signals with a carrier; and

(f) transmitting a composite signal created by adding the modulated signals,

wherein the complex spreading step and the complex scrambling step are arranged to improve the PAR (Peak-to-Average power Ratio) characteristic of the transmitter, and

wherein the second complex-domain scrambling codes (C_scramble,I[n]+jC_scramble,Q[n]) in the scrambling step are given by the following equations in terms of the primary scrambling codes (C₁[n], C₂[n];

(a) when the spreading data vary,

C_scramble,I[n]+jC_scramble,Q[n]=C₁[n]+C₂[n]; and

(b) when the spreading data do not vary,

C_scramble,I[n]+jC_scramble,Q[n]=−

C₂[n]C_scramble,Q[n−

1]H_b[n−

1]H_b[n]+jC₂[n]

C_scramble,I[n−

1]H₁[n−

1]H_a[n].

2. A transmitting method in CDMA (Code Division Multiple Access) systems with a transmitting apparatus and receiving apparatus, comprising the steps of:

(a) generating a pilot signal and transmitting data signals for several channels with different information, said data signals including a pair of data signals and additional data signals;

(b) supplying a pair of the data signals to a complex multiplier and spreading the pair of the data signals with complex orthogonal codes to obtain complex valued first spread signals, and spreading the additional data signals with complex orthogonal codes to obtain second spread signals;

{circle around (c)}) adding the first complex valued spread and the second signals;

(d) scrambling the added complex valued signals using complex valued PN (Pseudo-Noise) sequences;

(e) modulating the scrambled signals with a carrier; and

(f) transmitting a composite signal created by adding the modulated signals,

wherein the complex spreading step and the complex scrambling step are arranged to improve the PAR (Peak-to-Average power Ratio) characteristic of the transmitter, and

wherein the orthogonal complex-domain spreading is performed with Hadamard codes and the scrambling codes for the complex-domain scrambling are produced using orthogonal Hadamard codes.

3. A transmitting method in CDMA (Code Division Multiple Access) systems with a transmitting apparatus and receiving apparatus, comprising the steps of:

(a) generating a pilot signal and transmitting data signals for several channels with different information, said data signals including a pair of data signals and additional data signals;

(b) supplying a pair of the data signals to a complex multiplier and spreading the pair of the data signals with complex orthogonal codes to obtain complex valued first spread signals, and spreading the additional data signals with complex orthogonal codes to obtain second spread signals;

{circle around (c)}) adding the first complex valued spread and the second signals;

(d) scrambling the added complex valued signals using complex valued PN (Pseudo-Noise) sequences;

(e) modulating the scrambled signals with a carrier; and

(f) transmitting a composite signal created by adding the modulated signals,

wherein the complex spreading step and the complex scrambling step are arranged to improve the PAR (Peak-to-Average power Ratio) characteristic of the transmitter, and

the orthogonal complex-domain spreading is performed with Walsh codes and the scrambling codes for the complex-domain scrambling are produced using orthogonal Hadamard codes.

4. A transmitting method in CDMA (Code Division Multiple Access) systems with a transmitting apparatus and receiving apparatus, comprising the steps of:

(a) generating a pilot signal and transmitting data signals for several channels with different information, said data signals including a pair of data signals and additional data signals;

(b) supplying a pair of the data signals to a complex multiplier and spreading the pair of the data signals with complex orthogonal codes to obtain complex valued first spread signals, and spreading the additional data signals with complex orthogonal codes to obtain second spread signals;

{circle around (c)}) adding the first complex valued spread and the second signals;

(d) scrambling the added complex valued signals using complex valued PN (Pseudo-Noise) sequences;

(e) modulating the scrambled signals with a carrier; and

(f) transmitting a composite signal created by adding the modulated signals,

wherein the complex spreading step and the complex scrambling step are arranged to improve the PAR (Peak-to-Average power Ratio) characteristic of the transmitter, and

the orthogonal complex-domain spreading is performed with Gold codes and the scrambling codes for the complex-domain scrambling are produced using orthogonal Hadamard codes.

5. A transmitting apparatus in CDMA (Code Division Multiple Access) systems with a transmitting apparatus and receiving apparatus, comprising:

(a) means for generating a pilot signal and transmitting data signals for several channels with different information;

(b) means for controlling the signal-gains of the channels (c) means for spreading the gain-controlled signal for each channel;

(d) a first complex-domain multiplying means for performing a first orthogonal complex-domain spreading with the input of the transmitting data of the supplementary channels and of the OVSF (Orthogonal Variable Spreading Factor) codes;

(e) means for adding the output of the first complex-domain multiplying means and the spread signal;

(f) a spreading modulator, comprising a complex-domain multiplier and a scrambling code generator, for modulating the added signal;

(g) means for amplifying low-pass filtered signal power;

(h) means for modulating the amplified signal to the desired frequency band; and

(i) means for adding the modulated signal.

6. A receiving apparatus in CDMA (Code Division Multiple Access) systems with a transmitting apparatus and receiving apparatus, comprising:

(a) means for demodulating the transmitted signal from an antenna using the same carrier used in the transmitter;

(b) a spreading de-modulator, comprising a scrambling code generator and complex-domain multiplying means, for de-scrambling the modulated signal;

(c) means for de-spreading the de-scrambled signal to get the desired channel by integrating for the symbol period proportional to the data rate of the corresponding channel; and

(d) second complex-domain multiplying means for correcting the phase of the de-spread signal.

7. A receiving apparatus as defined in claim 6, wherein the carrier used in the demodulating means of step (a) in claim 6 include the same waves used in the transmitter.