阅读说明：本技术 一种调谐射频架构的2-fsk唤醒接收器及其解调方法 (2-FSK awakening receiver of tuning radio frequency architecture and demodulation method thereof ) 是由 马涛 习汉晨 张典典 于 2019-08-09 设计创作，主要内容包括：本发明涉及一种调谐射频架构的2-FSK唤醒接收器及其解调方法,所述解调方法包括：获取2-FSK射频信号；根据所述2-FSK射频信号,得到包络信号；在一个符号时间内对所述包络信号进行均匀采样,得到具有N个样本的向量；对所述向量分别进行第一频率滤波处理和第二频率滤波处理,得到第一频率滤波值和第二频率滤波值；比较所述第一频率滤波值和所述第二频率滤波值的大小,根据比较结果输出解调信号。本实施例的解调方法运算简便,且与相位误差无关,本实施例的2-FSK唤醒接收器避免了耗电的本机振荡器,降低了唤醒接收器的功耗,采用窄带FSK调制可以使接收器获得更高的灵敏度。(The invention relates to a 2-FSK awakening receiver of a tuning radio frequency framework and a demodulation method thereof, wherein the demodulation method comprises the following steps: acquiring a 2-FSK radio frequency signal; obtaining an envelope signal according to the 2-FSK radio frequency signal; uniformly sampling the envelope signal within a symbol time to obtain a vector with N samples; respectively carrying out first frequency filtering processing and second frequency filtering processing on the vector to obtain a first frequency filtering value and a second frequency filtering value; and comparing the first frequency filtering value with the second frequency filtering value, and outputting a demodulation signal according to a comparison result. The demodulation method of the embodiment is simple and convenient to operate and has no relation with phase errors, the 2-FSK awakening receiver of the embodiment avoids a power-consuming local oscillator, the power consumption of the awakening receiver is reduced, and the narrow-band FSK modulation is adopted to enable the receiver to obtain higher sensitivity.)

1. A demodulation method for a 2-FSK wake-up receiver for tuning a radio frequency architecture, comprising:

s1: acquiring a 2-FSK radio frequency signal X (t),

X(t)＝Acos(2πf_RFt)cos(2πf_IFt+θ),0＜t＜T，

wherein A represents the amplitude of the radio frequency signal, f_RFRepresenting the frequency of the radio-frequency signal, f_IFRepresents the frequency of the intermediate frequency signal, theta represents the phase error, and T represents a symbol time;

s2: obtaining an envelope signal Y (t) according to the 2-FSK radio frequency signal X (t);

s3: uniformly sampling the envelope signal y (t) within a symbol time to obtain a vector X having N samples;

s4: respectively carrying out first frequency filtering processing and second frequency filtering processing on the vector X to obtain a first frequency filtering value and a second frequency filtering value;

s5: and comparing the first frequency filtering value with the second frequency filtering value, and outputting a demodulation signal according to a comparison result.

2. The demodulation method according to claim 1, wherein said S2 includes:

performing band-pass filtering processing on the 2-FSK radio frequency signal X (t) to obtain a filtering signal;

envelope detection is carried out on the filtering signal to obtain an envelope signal Y (t),

Y(t)＝A|cos(2πf_IFt+θ)|,0＜t＜T；

performing Fourier series expansion on the envelope signal Y (t) to obtain a Fourier series expansion,

obtaining a set of frequency components Ω (f) in the Fourier series expansion_IF)：

Ω(f_IF)＝[2f_IF，4f_IF，8f_IF,…,∞]。

3. The demodulation method according to claim 2, wherein said S3 includes:

let f₁And f₂Respectively, the frequency of the 2-FSK radio frequency signal, the envelope signal y (T) obtained within one symbol time T is,

Y(t)＝A|cos(2πf₁t + θ) |, 0 < T < T, or

Y(t)＝A|cos(2πf₂t+θ)|，0＜t＜T

Wherein f is₁＝k₁/T，f₂＝k₂T, T denotes a symbol time, k₁And k₂Is an arbitrary natural number, and

-N times uniformly sampling said envelope signal Y (T) within a symbol time T, resulting in a vector X having N samples,

X＝[Y(t₁),Y(t₂),...,Y(t_N)]^T，

where T denotes transpose and N denotes the number of samples.

4. The demodulation method according to claim 3, wherein said S4 comprises:

s41: performing the first frequency filtering process on the vector X to obtain a first frequency filtered value m1,

wherein T represents transposition, and N represents the number of samples;

s42: carrying out second frequency filtering processing on the vector X to obtain a second frequency filtering value m₂，

Where T denotes transpose and N denotes the number of samples.

5. The demodulation method according to claim 4, wherein said S5 comprises:

comparing the first frequency filtered value m₁And said second frequency filtered value m₂The size of (a) is (b),

if m₁>m₂Then the output demodulation signal is at frequency f₁The signal of (a) is received,

if m₁<m₂Then the output demodulation signal is at frequency f₂Of the signal of (1).

6. A 2-FSK wake-up receiver for tuning a radio frequency architecture, comprising: an antenna (1), a band-pass filter (2), an envelope detector (3) and a control module (4) which are connected in sequence, wherein,

the antenna (1) is used for acquiring a 2-FSK radio frequency signal X (t);

the band-pass filter (2) is used for performing band-pass filtering processing on the 2-FSK radio frequency signal X (t) to obtain a filtering signal;

the envelope detector (3) is used for carrying out envelope detection on the filtered signal to obtain an envelope signal Y (t);

and the control module (4) is used for sampling the envelope signal Y (t) and demodulating the envelope signal Y (t) to obtain a demodulation signal.

7. 2-FSK Wake-up receiver of a tuned radio frequency architecture according to claim 6, characterized in that the control module (4) comprises a sampling unit (41), a first frequency filter (42), a second frequency filter (43) and a decider (44), wherein,

the sampling unit (41) is configured to uniformly sample the envelope signal y (t) within one symbol time, resulting in a vector X having N samples;

the first frequency filter (42) is used for carrying out first frequency filtering processing on the vector X to obtain a first frequency filtering value m₁；

The second frequency filter (43) is used for carrying out second frequency filtering processing on the vector X to obtain a second frequency filtering value m₂；

The decision device (44) is used for comparing the first frequency filtering value m₁And said second frequency filtered value m₂And outputs a demodulation signal according to the comparison result.

8. The tuned radio frequency architecture 2-FSK wake-up receiver according to claim 7, wherein the control module (4) further comprises an enable signal unit (45), the enable signal unit (45) being connected to an input of the envelope detector (2) for generating an enable signal, the envelope detector (2) being enabled at sampling time and disabled at non-sampling time in accordance with the enable signal.

9. The tuned radio frequency architecture 2-FSK wake-up receiver according to claim 6, characterized in that the control module (4) is a single chip.

10. The tuned radio frequency architecture 2-FSK wake-up receiver according to claim 7, characterized in that the sampling unit (41) is an analog-to-digital converter.

Technical Field

The invention belongs to the technical field of awakening receivers, and particularly relates to a 2-FSK awakening receiver of a tuning radio frequency architecture and a demodulation method thereof.

Background

In recent years, wake-up receivers (WuR) have become an emerging technology for event-driven internet of things sensing applications. It can continuously monitor the wireless channel with limited power consumption and immediately wake up the main receiver when the expected traffic arrives. As a result, a large amount of idle listening power in the internet of things is saved, making the internet of things devices likely to be maintenance free in a few years.

Power consumption and RF (Radio Frequency) power sensitivity are key requirements for WuR design, significantly different from the data rate and energy efficiency per bit of interest when designing conventional receivers. The work currently associated with WuR can be largely divided into two categories: RF receiver architecture design and bit-level sampling. In the first class of operation, new low power receiver architectures are being elaborated by eliminating or changing the power consuming components of conventional receivers, with this type of WuR having a power sensitivity of less than-70 dbm. In the second category of operation, symbol-level sampling techniques are used for power consumption reduction, which operate the RF front-end circuitry intermittently rather than continuously to save power, the method typically having almost the same sensitivity as its corresponding conventional receiver without substantially modifying the conventional architecture. Therefore, this type of WuR is generally higher in sensitivity than the first type. But this type of research work has focused primarily On OOK (On-Off Keying) modulation, which is typically less than-90 dBm sensitive.

In order to further improve the sensitivity (to be below-100 dBm), it is necessary to provide a wake-up receiver with a new architecture and a demodulation method thereof.

Disclosure of Invention

In order to solve the above problems in the prior art, the present invention provides a 2-FSK wakeup receiver for tuning a radio frequency architecture and a demodulation method thereof. The technical problem to be solved by the invention is realized by the following technical scheme:

the invention provides a demodulation method of a 2-FSK awakening receiver applied to a tuning radio frequency architecture, which comprises the following steps:

s1: acquiring a 2-FSK radio frequency signal X (t),

X(t)＝Acos(2πf_RFt)cos(2πf_IFt+θ),0＜t＜T，

wherein A represents the amplitude of the radio frequency signal, f_RFRepresenting the frequency of the radio-frequency signal, f_IFRepresents the frequency of the intermediate frequency signal, theta represents the phase error, and T represents a symbol time;

s2: obtaining an envelope signal Y (t) according to the 2-FSK radio frequency signal X (t);

s3: uniformly sampling the envelope signal y (t) within a symbol time to obtain a vector X having N samples;

s4: respectively carrying out first frequency filtering processing and second frequency filtering processing on the vector X to obtain a first frequency filtering value and a second frequency filtering value;

s5: and comparing the first frequency filtering value with the second frequency filtering value, and outputting a demodulation signal according to a comparison result.

In an embodiment of the present invention, the S2 includes:

performing band-pass filtering processing on the 2-FSK radio frequency signal X (t) to obtain a filtering signal;

envelope detection is carried out on the filtering signal to obtain an envelope signal Y (t),

Y(t)＝A|cos(2πf_IFt+θ)|,0＜t＜T；

performing Fourier series expansion on the envelope signal Y (t) to obtain a Fourier series expansion,

obtaining a set of frequency components Ω (f) in the Fourier series expansion_IF)，

Ω(f_IF)＝[2f_IF，4f_IF，8f_IF,…,∞]。

In an embodiment of the present invention, the S3 includes:

let f₁And f₂Respectively, the frequency of the 2-FSK radio frequency signal, the envelope signal y (T) obtained within one symbol time T is,

Y(t)＝A|cos(2πf₁t + θ) |, 0 < T < T, or

Y(t)＝A|cos(2πf₂t+θ)|，0＜t＜T

Wherein f is₁＝k₁/T，f₂＝k₂T, T denotes a symbol time, k₁And k₂Is an arbitrary natural number, and

-N times uniformly sampling said envelope signal Y (T) within a symbol time T, resulting in a vector X having N samples,

X＝[Y(t₁),Y(t₂),...,Y(t_N)]^T，

where T denotes transpose and N denotes the number of samples.

In one embodiment of the present invention, the 4 comprises:

s41: the vector X is subjected to the first frequency filtering processing to obtain a first frequency filtering value m₁，

Wherein T represents transposition, and N represents the number of samples;

s42: carrying out second frequency filtering processing on the vector X to obtain a second frequency filtering value m₂，

Where T denotes transpose and N denotes the number of samples.

In an embodiment of the present invention, the S5 includes:

comparing the first frequency filtered value m₁And said second frequency filtered value m₂The size of (a) is (b),

if m₁>m₂Then the output demodulation signal is at frequency f₁The signal of (a) is received,

if m₁<m₂Then the output demodulation signal is at frequency f₂Of the signal of (1).

The invention also provides a 2-FSK wake-up receiver of a tuned radio frequency architecture, comprising: the antenna, the band-pass filter, the envelope detector and the control module are connected in sequence, wherein,

the antenna is used for acquiring a 2-FSK radio frequency signal X (t);

the band-pass filter is used for performing band-pass filtering processing on the 2-FSK radio frequency signal X (t) to obtain a filtering signal;

the envelope detector is used for carrying out envelope detection on the filtering signal to obtain an envelope signal Y (t);

and the control module is used for sampling the envelope signal Y (t) and demodulating the envelope signal Y (t) to obtain a demodulated signal.

In one embodiment of the invention, the control module comprises a sampling unit, a first frequency filter, a second frequency filter, and a decider, wherein,

the sampling unit is used for uniformly sampling the envelope signal Y (t) in one symbol time to obtain a vector X with N samples;

the first frequency filter is used for carrying out first frequency filtering processing on the vector X to obtain a first frequency filtering value m₁；、

The second frequency filter is used for carrying out second frequency filtering processing on the vector X to obtain a second frequency filtering value m₂；

The decision device is used for comparing the first frequency filtering value m₁And said second frequency filtered value m₂And outputs a demodulation signal according to the comparison result.

In one embodiment of the invention, the control module further comprises an enable signal unit, the enable signal unit is connected to an input terminal of the envelope detector and is used for generating an enable signal, and the envelope detector is enabled at a sampling time and disabled at a non-sampling time according to the enable signal.

In one embodiment of the invention, the control module is a single chip microcomputer.

In one embodiment of the invention, the sampling unit is an analog-to-digital converter.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a 2-FSK awakening receiver of a tuning radio frequency architecture, compared with the traditional superheterodyne FSK awakening receiver, a local oscillator consuming power is not arranged, so that the power consumption of the awakening receiver is reduced; compared with the OOK modulation awakening receiver of the traditional tuning radio frequency architecture, the invention adopts the narrow-band FSK modulation, so that the receiver can obtain higher receiving sensitivity. Moreover, a new demodulation method is provided for the 2-FSK wake-up receiver, the method is simple and convenient to operate, and the demodulation method is independent of phase errors.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are described in detail with reference to the accompanying drawings.

Drawings

Fig. 1 is a flowchart of a demodulation method applied to a 2-FSK wake-up receiver of a tuned radio frequency architecture according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a 2-FSK radio frequency signal according to an embodiment of the present invention;

fig. 3 is a schematic diagram of an envelope signal provided by an embodiment of the present invention;

fig. 4 is a schematic diagram of an envelope signal spectrum provided by an embodiment of the present invention.

Fig. 5 is a block diagram of a 2-FSK wake-up receiver for tuning a radio frequency architecture according to an embodiment of the present invention.

Detailed Description

To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following describes a 2-FSK wakeup receiver with a tuned rf architecture and a demodulation method thereof according to the present invention in detail with reference to the accompanying drawings and the detailed description.

The foregoing and other technical matters, features and effects of the present invention will be apparent from the following detailed description of the embodiments, which is to be read in connection with the accompanying drawings. The technical means and effects of the present invention adopted to achieve the predetermined purpose can be more deeply and specifically understood through the description of the specific embodiments, however, the attached drawings are provided for reference and description only and are not used for limiting the technical scheme of the present invention.