Generating method and device, receiving method and device for dual-frequency constant envelope signal with four spreading signals

• US 9,680,594 B2
• Filed: 11/22/2013
• Issued: 06/13/2017
• Est. Priority Date: 11/23/2012
• Status: Active Grant

• Current Assignee: Tsinghua University
• Original Assignee: Tsinghua University
• Inventors: Yao, Zheng, Lu, Mingquan
• Primary Examiner(s): Lee, Andrew
• Application Number:
  US14/443,413
• Publication Number:
  US 20160191187A1
• Time in Patent Office: 1,299 Days
• CPC Class Codes: G01S 19/02 Details of the space or ground control segments
• CPC Class Codes: G01S 19/30 code related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04J 13/0003 Code application, i.e. aspects relating to how codes are applied to form multiplexed channels
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes

Abstract

The application relates to a generating method and device, receiving method and device for a dual-frequency constant envelope multiplexed signal with four spreading signals. According to the method, the four baseband spreading signals s₁(t), s₂(t), s₃(t), s₄(t) can be modulated to a frequency f₁ and a frequency f₂ respectively, so as to generate the constant envelope multiplexed signal on a radio carrier frequency f_p=(f₁+f₂)/2, where the signals s₁(t) and s₂(t) are modulated on the frequency f₁ with carrier phases orthogonal to each other, the signals s₃(t) and s₄(t) are modulated on the frequency f₂ with carrier phases orthogonal to each other, f₁>f₂. The method comprises: determining a power ratio allocated to the four baseband spreading signals s₁(t), s₂(t), s₃(t), s₄(t) in the constant envelope multiplexed signal; storing an additional phase lookup table, wherein the table includes additional phases of an in-phase baseband component I(t) and a quadrature-phase baseband component Q(t) of the constant envelope multiplexed signal; obtaining an additional phase θ of a segment of the current time by looking up the additional phase lookup table; and generating an in-phase baseband component I(t) and a quadrature-phase baseband component Q(t) of the constant envelope multiplexed signal, and generating the constant envelope multiplexed signal S_RF(t) based on the obtained additional phase θ.

Claims

1. A method for generating a dual-frequency constant envelope multiplexed signal with four spreading signals, in which the four baseband spreading signals s₁(t), s₂(t), s₃(t), s₄(t) are modulated to a frequency f₁ and a frequency f₂ respectively, so as to generate the constant envelope multiplexed signal on a radio carrier frequency

2. The method as claimed in claim 1, wherein the additional phase lookup table is configured by:

obtaining a preset in-phase baseband component Î

(t) and a preset quadrature-phase baseband component {circumflex over (Q)}(t);

{circumflex over (I)}(t)=Z(t)×

sgn [sin(2π

f_st+φ

(t))],

{circumflex over (Q)}(t)=Z′

(t)×

sgn [sin(2π

f_st+φ

′

(t))],

wherein sgn stands for the sign function

3. The method as claimed in claim 2, wherein the procedure of dividing a subcarrier period T_s of the baseband spreading signal into multiple segments based on the determined power ratio of the four baseband spreading signals s₁(t), s₂(t), s₃(t), s₄(t) comprises:

calculating an additional phase θ

=atan 2({circumflex over (Q)}(t), Î

(t)) in a subcarrier period T_s of the baseband spreading signal for each state of value combination of the four baseband spreading signals s₁(t), s₂(t), s₃(t), s₄(t) based on the determined power ratio of the four baseband spreading signals s₁(t), s₂(t), s₃(t), s₄(t); and

determining phase-shifting time points of the additional phase θ

in the subcarrier period T_s of the baseband spreading signal, and dividing the subcarrier period T_s of the baseband spreading signal into multiple segments according to the phase-shifting time points.

4. The method as claimed in claim 1, wherein the power ratio of the four baseband spreading signals s₁(t), s₂(t), s₃(t), s₄(t) is 1:

3;

1;

3, and the subcarrier period T_s of the baseband spreading signal is divided into 12 segments with equal length, and the additional phase lookup table is in the form of Table 1 or Table 2;

8. A signal receiving method for receiving the constant envelope multiplexed signal as claimed in any of claims 1 through 4 which comprises:

receiving the constant envelope multiplexed signal;

demodulating a signal component modulated on the frequency f₁ of the received constant envelope multiplexed signal, and for demodulating a signal component modulated on the frequency f₂ of the received constant envelope multiplexed signal; and

obtaining baseband spreading signals the demodulated s₁(t) and s₂(t) based on the demodulated signal component which is modulated on the frequency f₁, and for obtaining baseband spreading signals s₃(t) and s₄(t) based on the demodulated signal component which is modulated on the frequency f₂.

10. A signal receiving method for receiving the constant envelope multiplexed signal as claimed in any of claims 1 through 4 , wherein the signal receiving method comprises:

storing the additional phase lookup table;

receiving the constant envelope multiplexed signal;

demodulating the received constant envelope multiplexed signal through a central frequency of

12. A signal receiving method for receiving the constant envelope multiplexed signal as claimed in any of claims 1 through 4 wherein the signal receiving method comprises:

storing the mentioned additional phase lookup table;

receiving, filtering and amplifying the constant envelope multiplexed signal, wherein a central frequency of the filtering and amplifying is set at

14. A system for receiving a constant envelope multiplexed signal generated by the method or the device for generating the dual-frequency constant envelope multiplexed signal with four spreading signals as claimed in any preceding claims, the system comprising:

a receiving unit for receiving the constant envelope multiplexed signal;

a demodulation unit for demodulating a signal component modulated on the frequency f₁ of the received constant envelope multiplexed signal, and for demodulating a signal component modulated on the frequency f₂ of the received constant envelope multiplexed signal;

a microprocessor and a non-transitory computer readable medium, wherein the non-transitory computer readable medium includes instructions executable by the microprocessor to;

obtain the baseband spreading signals s₁(t) and s₂(t) based on the demodulated signal component which is modulated on the frequency f₁, and

obtain the baseband spreading signals s₃(t) and s₄(t) base on the demodulated signal component which is modulated on the frequency.

15. A method for receiving a constant envelope multiplexed signal generated by the method or the device for generating the dual-frequency constant envelope multiplexed signal with four spreading signals as claimed in any preceding claims, the method comprising:

providing a receiving unit for receiving a constant envelope multiplexed signal; and

in a processing unit including a microprocessor and a non-transitory computer readable medium;

storing an additional phase lookup table;

receiving the constant envelope multiplexed signal;

demodulating the received constant envelope multiplexed signal through a central frequency

5. A device for generating a dual-frequency constant envelope multiplexed signal with four spreading signals, in which the four baseband spreading signals s₁(t), s₂(t), s₃(t), s₄(t) are modulated to a frequency f₁ and a frequency f₂ respectively, so as to generate the constant envelope multiplexed signal on a radio carrier frequency

6. The device as claimed in claim 5, wherein the power ratio of the four baseband spreading signals s₁(t), s₂(t), s₃(t), s₄(t) is 1:

3;

1;

3, and the subcarrier period T_s of the baseband spreading signal is divided into 12 segments with equal length, and the additional phase lookup table stored in the additional phase lookup table storing unit is in the form of Table 1 or Table 2;

7. A signal receiving device to receive the constant envelope multiplexed signal as claimed in any of claims 5 through 6 , which comprises:

a receiving unit for receiving the constant envelope multiplexed signal;

a demodulation unit for demodulating a signal component modulated on the frequency f₁ of the received constant envelope multiplexed signal, and for demodulating a signal component modulated on the frequency f₂ of the received constant envelope multiplexed signal; and

a processing unit for obtaining baseband spreading signals s₁(t) and s₂(t) based on the demodulated signal component which is modulated on the frequency f₁, and for obtaining baseband spreading signals s₃(t) and s₄(t) based on the demodulated signal component which is modulated on the frequency f₂.

9. A signal receiving device to receive the constant envelope multiplexed signal as claimed in any of claims 5 through 6 , wherein the additional phase lookup table is stored in the signal receiving device and the signal receiving device comprises:

a receiving unit for receiving the constant envelope multiplexed signal;

a demodulation unit for demodulating the received constant envelope multiplexed signal with a central frequency of

11. A signal receiving device to receive the constant envelope multiplexed signal as claimed in any of claims 5 through 6 , wherein the additional phase lookup table is stored in the signal receiving device and the signal receiving device comprises:

a receiving unit for receiving, filtering and amplifying the constant envelope multiplexed signal, wherein a central frequency of the filtering and amplifying is set at

13. A system for generating a dual-frequency constant envelope multiplexed signal with four spreading signals, in which the four baseband spreading signals s₁(t), s₂(t), s₃(t), s₄(t) are modulated to a frequency f₁ and a frequency f₂ respectively, so as to generate the constant envelope multiplexed signal on a radio carrier frequency