CN113037322A - System and method for improving Wi-SUN network communication link performance - Google Patents

Abstract

The invention discloses a system and a method for improving the performance of a Wi-SUN network communication link, wherein the system comprises a transmitter, the transmitter is connected with a radio frequency switch through a first impedance matching module, a PA (power amplifier) and a second impedance matching module in sequence, the radio frequency switch is connected with a receiver through an LNA (low noise amplifier), a third impedance matching module in sequence, and the first impedance matching module is connected with the PA and is also connected with the radio frequency switch through a Bypass loop. The method comprises the following steps: the LNA starts operating in a default mode Gain mode; setting a signal level threshold and monitoring; when the signal level threshold is reached, the LNA is switched to a working mode Bypass mode; below the signal level threshold, the LNA automatically switches back to the default mode Gain mode. According to the technical scheme, the link budget of the communication system is effectively improved by improving the transmitting power and the receiving sensitivity, and the LNA or the Wi-SUN IC is protected from being damaged by large signals under extreme conditions while the link performance of the Wi-SUN communication network is improved.

Description

System and method for improving Wi-SUN network communication link performance

Technical Field

The invention relates to the technical field of communication, in particular to a system and a method for improving the performance of a Wi-SUN network communication link.

Background

The Wi-SUN communication technology is a standard wireless communication network, and the flexible networking technology, the enterprise-level security mechanism and the interconnection network standard make the Wi-SUN communication technology active in the application field of the Internet of things. The hardware system is used as the basis of the whole radio frequency communication system, and the performance of a communication link can directly determine the wireless data receiving and transmitting success rate, the communication distance, the system stability and the like. The link performance of the communication system can be expressed by link budget parameters in most cases, and the link budget formula of the wireless free wave is as follows:

LinkBudget(dB)＝Pt(dBm)-Sens(dBm)

wherein linkbead is link budget, Pt is maximum transmission power of the transmitter, and Sens is optimal receiving sensitivity of the receiver. From the above equation, two methods are used to increase the link budget: 1, increasing the transmitting power of a transmitter; and 2, optimizing the receiving sensitivity of the receiver.

The common method for increasing the transmission power is to add a radio frequency power amplifier PA between the output end of the transmitter and the antenna, and single-stage or multi-stage power amplification can be selected according to the power gain required to be increased. Since the transmission power of radio equipment is not defined in the same standard in each country, the transmission power of a transmitter must be set too high according to local regulations. At this time, it is necessary to raise the noise figure of the system from the viewpoint of raising the receiver sensitivity to achieve the purpose of optimizing the receiving sensitivity, and a common method is to add a low noise amplifier LNA to the antenna and the receiver input terminal.

The scheme in the existing Wi-SUN communication network can achieve the goal of improving the budget of the communication link, but ignores a case: when the transmitter is located close to the receiver's antenna and the transmit power is large enough, for example 30dBm, the signal power entering the receiver antenna may reach more than 25dBm through the antenna's radiative coupling. The LNA of the RF front end is easy to damage, even if the selected LNA maximum input power can resist the impact of a large signal, the maximum input signal power of most Wi-SUN integrated chip IC receiving ends in the current world is not too large, and the maximum input signal power is difficult to escape. When the LNA or the Wi-SUN IC is damaged by a large signal, the radio frequency communication system is directly paralyzed, and the function of wireless communication cannot be continuously realized.

Chinese patent document CN109842868A discloses a "frame aggregation, network setup frame sending method and device". The first forwarding node equipment receives a first data frame and a second data frame, wherein the first data frame comprises a first MAC (media access control) head and a first MSDU (multiple mobile data unit), the second data frame comprises a second MAC head and a second MSDU, and the destination MAC addresses in the first MAC head and the second MAC head are the same; generating a first aggregation frame, wherein the first aggregation frame comprises an aggregation MAC header and an aggregation MSDU, a destination MAC address in the aggregation MAC header is the same as the destination MAC address, the aggregation MSDU comprises a first sub MSDU and a second sub MSDU, the first sub MSDU comprises the first MSDU and a source MAC address of the first data frame, and the second sub MSDU comprises the second MSDU and a source MAC address of the second data frame; the second forwarding node device transmits the first aggregated frame. The technical scheme needs larger signal receiving and processing capacity when facing a wider range, and can not protect an LNA or a Wi-SUN IC from being damaged by large signals under extreme conditions while improving the link performance of the Wi-SUN communication network.

Disclosure of Invention

The invention mainly solves the technical problem that the prior technical scheme can not protect an LNA or a Wi-SUN IC from being damaged by a large signal under extreme conditions while improving the link performance of the Wi-SUN communication network, and provides a system and a method for improving the link performance of the Wi-SUN communication network. Meanwhile, Bypass loops are designed in the PA and LNA circuits, the Bypass loops are switched from Gain modes to Bypass modes under the condition of need, radio frequency limiter circuits are respectively designed in front of and behind the LNA for protecting the LNA and the Wi-SUN integrated chip IC, and the LNA or the Wi-SUN IC is protected from being damaged by large signals under the extreme condition while the link performance of the Wi-SUN communication network is improved.

The technical problem of the invention is mainly solved by the following technical scheme:

the utility model provides a system for be used for promoting Wi-SUN network communication link performance, includes the transmitter, the transmitter links to each other with the radio frequency switch through first impedance matching module, PA, second impedance matching module in proper order, the radio frequency switch links to each other through LNA, third impedance matching module and receiver in proper order, first impedance matching module links to each other through Bypass return circuit and radio frequency switch when linking to each other with the PA. Both PA and LNA circuits are designed with Bypass loops, and the Bypass loops are switched from Gain mode to Bypass mode if necessary.

Preferably, the front end and the rear end of the LNA are respectively provided with a radio frequency limiter. The RF limiter circuit is designed before and after the LNA for protecting the LNA and the Wi-SUN IC.

Preferably, the radio frequency limiter comprises a first blocking capacitor and a second blocking capacitor which are connected in series between the input end and the output end, the first blocking capacitor (8.2) and the second blocking capacitor are connected in series and are grounded through a PIN diode, and the radio frequency limiter further comprises an inductor connected with the PIN diode in parallel. The direct current blocking capacitor mainly prevents an external direct current signal from entering the radio frequency amplitude limiter to cause misoperation, the inductor connected with the PIN diode in parallel provides a direct current bias loop, and the PIN diode realizes the radio frequency amplitude limiting function.

Preferably, the LNA includes two modes, a Bypass mode and a Gain mode. In order to reduce the volume, the LNA with the Bypass mode and the Gain mode is selected.

A working method of a system for improving Wi-SUN network communication link performance comprises the following steps:

the lna starts operating in default mode Gain mode;

b. setting a signal level threshold and monitoring;

c. when the signal level threshold is reached, the LNA is switched to a working mode Bypass mode;

d. when the received signal is below the signal level threshold, the LNA automatically switches back to the default mode Gain mode.

Preferably, the step c is realized by the I/O control of the microcontroller to switch the working mode.

Preferably, when the LNA operation mode in step c is Bypass mode, the timing is switched back to the default mode Gain mode for a short time. And switching back to the default mode Gain mode for monitoring the signal level strength in real time.

The invention has the beneficial effects that:

1. by improving the transmitting power and the receiving sensitivity, the link budget of the communication system is effectively improved, so that the single-stage communication distance of the Wi-SUN network is increased, the same number of nodes can be accessed in the original Wi-SUN networking only by fewer stages, and the network stability is greatly improved.

2. The scheme can effectively solve the impact of strong signals on sensitive devices on a receiving link and play a role in enhancing the reliability of the system in consideration of the fact that the distance between the antennas of the terminal equipment is very close, namely the isolation between the antennas is very small when the Wi-SUN network is actually applied and arranged.

3. The LNA or the Wi-SUN IC is protected from large signals in extreme cases while improving the Wi-SUN communication network link performance.

Drawings

Fig. 1 is a schematic connection structure of the present invention.

Fig. 2 is a circuit diagram of an rf limiter according to the present invention.

Fig. 3 is a flow chart of the present invention.

In the figure, 1 transmitter, 2.1 first impedance matching, 2.2 second impedance matching, 2.3 third impedance matching, 3 PA, 4 Bypass loop, 5 rf switch, 6 antenna, 7 LNA, 8 rf limiter, 8.1 input terminal, 8.2 first dc blocking capacitor, 8.3 second dc blocking capacitor, 8.4 output terminal, 8.5 PIN diode, 8.6 inductor, 9 receiver.

Detailed Description

The technical scheme of the invention is further specifically described by the following embodiments and the accompanying drawings.

Example (b): a system for promoting Wi-SUN network communication link performance of this embodiment, as shown in fig. 1, includes transmitter 1, transmitter 1 passes through first impedance matching module 2.1, PA3, second impedance matching module 2.2 in proper order and links to each other with radio frequency switch 5, radio frequency switch 5 passes through LNA7 in proper order, third impedance matching module 2.3 and receiver 9 link to each other, first impedance matching module 2.1 links to each other with PA3 and links to each other with radio frequency switch 5 through Bypass return circuit 4 simultaneously. The front end and the rear end of the LNA7 are respectively provided with a radio frequency amplitude limiter 8. The RF limiter circuit is designed before and after the LNA for protecting the LNA and the Wi-SUN IC. The LNA7 includes two modes, Bypass mode and Gain mode, and in order to reduce the size, the LNA with the two modes is selected. Both PA and LNA circuits are designed with Bypass loops, and the Bypass loops are switched from Gain mode to Bypass mode if necessary.

As shown in fig. 2, the rf limiter 8 includes a first blocking capacitor 8.2 and a second blocking capacitor 8.3 connected in series between an input terminal 8.1 and an output terminal 8.3, where the blocking capacitors mainly prevent external dc signals from entering the rf limiter to cause malfunction. The first blocking capacitor 8.2 and the second blocking capacitor 8.3 are connected in series and are grounded through a PIN diode 8.5, and the PIN diode realizes the radio frequency amplitude limiting effect. And the inductor 8.6 is connected with the PIN diode 8.5 in parallel, and the inductor connected with the PIN diode in parallel provides a direct current bias loop.

In operation, when the limiter input receives a small signal (below the PIN diode limiting threshold), the PIN diode presents a large impedance, which corresponds to an open circuit state for radio frequency reception, resulting in a low insertion loss (generally below 0.5 dB). When an input signal exceeds an amplitude limiting threshold value, the impedance of the PIN diode starts to be reduced, so that the impedance on the radio frequency loop is in a mismatched state, and at the moment, the output signal of the amplitude limiter starts to be reduced; when the input signal continues to increase, the leakage power of the limiter is kept at a constant value, and most of the signal returns to the signal source to play a role in protecting a back-end circuit (LNA or RFIC). When the large signal is removed, the PIN diode is restored to a large impedance state to reduce the influence on the received signal.

A method for operating a system for improving the performance of a Wi-SUN network communication link, as shown in fig. 3, includes the following steps:

lna7 starts operating in default mode Gain mode;

b. setting a signal level threshold and monitoring;

c. when the signal level threshold is reached, the LNA is controlled to be switched into a working mode Bypass mode through the I/O control of the microcontroller; when the LNA7 is in Bypass mode, the LNA7 is switched back to the default mode Gain mode for a short time at regular time for monitoring the signal level strength in real time.

d. The LNA7 automatically switches back to the default mode Gain mode when the received signal is below the signal level threshold.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.

Although terms like Bypass loop, rf limiter, etc. are used more often herein, the possibility of using other terms is not excluded. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed as being without limitation to any additional limitations that may be imposed by the spirit of the present invention.

Claims (7)

1. The utility model provides a system for be used for promoting Wi-SUN network communication link performance, its characterized in that, includes transmitter (1), transmitter (1) links to each other with radio frequency switch (5) through first impedance matching module (2.1), PA (3), second impedance matching module (2.2) in proper order, radio frequency switch (5) link to each other through LNA (7), third impedance matching module (2.3) and receiver (9) in proper order, link to each other through Bypass return circuit (4) and radio frequency switch (5) when first impedance matching module (2.1) link to each other with PA (3).

2. The system for improving the performance of the Wi-SUN network communication link according to claim 1, wherein the front end and the rear end of the LNA (7) are respectively provided with a radio frequency limiter (8).

3. The system for improving the performance of the Wi-SUN network communication link according to claim 2, wherein the radio frequency limiter (8) comprises a first dc blocking capacitor (8.2) and a second dc blocking capacitor (8.3) connected in series between the input terminal (8.1) and the output terminal (8.3), the first dc blocking capacitor (8.2) and the second dc blocking capacitor (8.3) are connected in series and are connected to the ground through a PIN diode (8.5), and the system further comprises an inductor (8.6) connected in parallel with the PIN diode (8.5).

4. The system for improving Wi-SUN network communication link performance according to claim 2, wherein the LNA (7) comprises two modes, Bypass mode and Gain mode.

5. A method of operating a system for improving the performance of a Wi-SUN network communication link, comprising the steps of:

the lna (7) starts operating in default mode Gain mode;

b. setting a signal level threshold and monitoring;

c. when the signal level threshold is reached, the LNA is switched to a working mode Bypass mode;

d. the LNA (7) automatically switches back to the default mode Gain mode when the received signal is below the signal level threshold.

6. The operating method of a system for improving Wi-SUN network communication link performance according to claim 5, wherein the step c is implemented by an I/O control of a microcontroller to switch the operating mode.

7. The method as claimed in claim 5, wherein the LNA (7) operating mode in step c is Bypass mode, and the default mode Gain mode is switched back to for a short time.

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