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

Patent metadata

Field	Value
Publication number	US-9680594-B2
Application number	US-201314443413-A
Country	US
Kind code	B2
Filing date	Nov 22, 2013
Priority date	Nov 23, 2012
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

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 s 1 (t), s 2 (t), s 3 (t), s 4 (t) can be modulated to a frequency f 1 and a frequency f 2 respectively, so as to generate the constant envelope multiplexed signal on a radio carrier frequency f p =(f 1 +f 2 )/2, where the signals s 1 (t) and s 2 (t) are modulated on the frequency f 1 with carrier phases orthogonal to each other, the signals s 3 (t) and s 4 (t) are modulated on the frequency f 2 with carrier phases orthogonal to each other, f 1 >f 2 . The method comprises: determining a power ratio allocated to the four baseband spreading signals s 1 (t), s 2 (t), s 3 (t), s 4 (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.

First claim

What is claimed is:

1. A method for generating a dual-frequency constant envelope multiplexed signal with four spreading signals, in which the four baseband spreading signals s 1 (t), s 2 (t), s 3 (t), s 4 (t) are modulated to a frequency f 1 and a frequency f 2 respectively, so as to generate the constant envelope multiplexed signal on a radio carrier frequency

f
p

=

f
1

+

f
2

2

,

where the signals s 1 (t) and s 2 (t) are modulated on the frequency f 1 with carrier phases orthogonal to each other, and the signals s 3 (t) and s 4 (t) are modulated on the frequency f 2 with carrier phases orthogonal to each other, f 1 >f 2 , wherein the method further comprises:
determining a power ratio allocated to the four baseband spreading signals s 1 (t), s 2 (t), s 3 (t), s 4 (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, and the table is configured by dividing a subcarrier period T s of the baseband spreading signal into multiple segments and by determining, at each segment of the multiple segments, an additional phase θ for a state among 16 states of value combination of the four baseband spreading signals s 1 (t), s 2 (t), s 3 (t), s 4 (t) in the constant envelope multiplexed signal, based on the determined power ratio of the four baseband spreading signals s 1 (t), s 2 (t), s 3 (t), s 4 (t);
obtaining, according to a segment of the subcarrier period of the baseband spreading signal and to a state of the value combination of the four baseband spreading signals s 1 (t), s 2 (t), s 3 (t) and s 4 (t) corresponding to the current time, an additional phase θ of a segment of the current time by looking up the additional phase lookup table;
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, where
S RF ( t )= I ( t )cos(2 πf p t )− Q ( t )sin(2 πf p t ),

I ( t )= A cos(θ),

Q ( t )= A sin(θ),

f
p

=

f
1

+

f
2

2

,

⁢

T
s

=

1

f
s

,

⁢

f
s

=

f
1

-

f
2

2

,

where A is the amplitude of the constant envelope multiplexed signal S RF (t).

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 s t +φ( t ))],

{circumflex over ( Q )}( t )= Z′ ( t )×sgn [sin(2π f s t +φ′( t ))],

wherein sgn stands for the sign function

sgn
⁡

(
x
)

=

{

+
1

,

x
≥
0

-
1

,

x
<
0

,

⁢

Z
⁡

(
t
)

=

-

(

c
1

⁢

s
1

⁡

(
t
)

+

Assignees

• Univ Tsinghua

Inventors

• Yao Zheng
• Lu Mingquan

Classifications

• G01S19/37

  Hardware or software details of the signal processing chain · CPC title

• H04B1/707

  using direct sequence modulation · CPC title

• G01S19/02

  Details of the space or ground control segments · CPC title

• G01S19/30

  code related {(G01S19/246 takes precedence)} · CPC title

• H04J13/0003 Primary

  Code application, i.e. aspects relating to how codes are applied to form multiplexed channels · CPC title