CN106960557A - A kind of multiple antennas automatic switching control equipment and method based on RSSI - Google Patents

Abstract

The invention discloses an RSSI-based multi-antenna automatic switching device and method, comprising one radio frequency module, eight SMA antenna interfaces, seven relays, auxiliary power supply and control switching circuit. The 8 SMA antenna interfaces are respectively connected to 1 wireless radio frequency module, 1 omnidirectional antenna and 6 directional antennas with a radiation angle of 65 degrees. The relay, the auxiliary power supply and the control switching circuit are used to realize the self-adaptive switching work of multiple antennas. The invention realizes self-adaptive multi-antenna switching by detecting RSSI and packet loss rate, can effectively improve network space multiplexing rate, increase network coverage area, save energy consumption and the like. It solves the problems of large-area monitoring system (such as large-area rice fields) due to large environmental interference, which leads to high packet loss rate of the monitoring system and poor real-time information collection.

Description

An RSSI-based multi-antenna automatic switching device and method

technical field

The invention relates to networking of wireless sensor networks based on hybrid antennas, in particular to an RSSI-based multi-antenna automatic switching device and method.

Background technique

Wireless sensor network (WSN) is one of the key technologies of the Internet of Things. It has attracted extensive attention of scholars at home and abroad, and the application of WSN technology to environmental monitoring and ecological research is one of the current research hotspots. WSN has the characteristics of self-organization, low power consumption, and high reliability. Combining wireless sensor networks with farmland parameter sensors can realize online real-time monitoring of large-scale and multi-point farmland parameters, which is very important for accelerating the informatization of agricultural production and improving the quality of crops. The quality and output are of great significance.

The agricultural monitoring system based on wireless sensor network is generally composed of sensor nodes, sink nodes and remote network monitoring terminals. Each sensor node distributed in the designated monitoring area is responsible for collecting the environmental parameters to be monitored, such as air temperature and humidity, light intensity, carbon dioxide concentration, soil temperature and moisture, and sending them to the sink node. Then the aggregation node uploads to the remote server through the GPRS module. The ability of sensor nodes and aggregation nodes to receive and forward data packets is not only related to the selected radio frequency module, but also inseparable from the antenna mounted on the radio frequency module.

At present, most of the wireless sensor network routing protocols are based on the omnidirectional antenna technology. In recent years, the research on the use of directional antennas in wireless sensor networks has gradually attracted attention. Compared with omnidirectional antennas, directional antennas have the advantages of improving network space multiplexing rate, increasing network coverage area, and saving energy consumption.

Contents of the invention

Aiming at the shortcomings of the prior art, the object of the present invention is to provide a multi-antenna automatic switching device and method based on RSSI (Received Signal Strength Indication), and realize adaptive antenna switching by detecting RSSI and packet loss rate.

In order to achieve the above object, a technical scheme of an RSSI-based multi-antenna automatic switching device of the present invention is: including 1 radio frequency module, 8 SMA antenna interfaces, 7 relays, auxiliary power supply, and control switching circuit.

The device includes 1 radio frequency module, 8 SMA antenna interfaces and 7 relays. The antenna interface of the wireless radio frequency module and the common terminal of the No. 1 relay are connected to the No. 1 SMA antenna interface. The normally closed contact of the No. 1 relay is connected to the No. 2 SMA antenna interface and connected to the omnidirectional antenna. The remaining normally closed contacts of No. 2-7 relays are respectively connected to No. 3-7 SMA antenna interfaces in turn and connected to a directional antenna with a radiation angle of 65 degrees. The normally open contact of relay No. 1 is connected to the common terminal of relay No. 2. The normally open contact of relay No. 2 is connected to the common terminal of relay No. 3. The normally open contact of relay No. 3 is connected to the common terminal of relay No. 4. The normally open contact of relay No. 4 is connected to the common terminal of relay No. 5. The normally open contact of relay No. 5 is connected to the common terminal of relay No. 6. The normally open contact of relay No. 6 is connected to the common terminal of relay No. 7. The normally open contact of the No. 7 relay is connected to the No. 8 SMA antenna interface.

Among the eight SMA antenna interfaces, the No. 1 SMA antenna interface is connected to the antenna interface of the radio frequency module. The No. 2 SMA antenna interface is connected to the omnidirectional antenna. The remaining 3-8 SMA antenna interfaces are connected to directional antennas with a radiation angle of 65 degrees.

In addition, the present invention also includes an RSSI-based multi-antenna automatic switching method, comprising the following steps:

a. Initialize the basic configuration of the wireless radio frequency module;

b. Set the transmit power of the radio frequency module to the minimum;

c. Switch the radio frequency module antenna to an omnidirectional antenna;

d. Obtain and judge whether the RSSI value of the radio frequency module is greater than the set threshold;

e. If the RSSI value in step d is greater than the set threshold, enter the normal sending and receiving mode, and this round of work is completed. Otherwise, start to switch directional antennas in turn, and return to step d; if the RSSI value does not reach the threshold after polling all directional antennas, the radio frequency module increases the transmit power by one level. And return to step d.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) The present invention is reasonable in design and strong in applicability, and adopts the mode of electronically controlled self-adaptive switching antenna. The networking performance of the wireless sensor network based on the device is improved.

(2) The present invention can increase the network coverage area, thereby increasing the monitoring area.

(3) The relay uses a photocoupler in the input and output internal circuits, which avoids the influence of the output terminal on the previous control circuit;

(4) The control circuit PMOS tube in the device has lower power consumption.

(5) The control circuit in the device is powered by DC 5V, and the low-voltage power supply can ensure the safety of the operator.

Description of drawings

Fig. 1 is a kind of RSSI-based multi-antenna automatic switching device and method structure schematic diagram of the present invention;

Fig. 2 is a schematic diagram of the present invention;

Fig. 3 is the working flowchart of antenna switching in the present invention;

detailed description

The present invention will be described in further detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

As shown in Figure 1, the device includes 1 radio frequency module, 8 SMA antenna interfaces, 7 relays, auxiliary power supply, and control switching circuit. The antenna can be switched adaptively according to the RSSI value of the radio frequency module. The antenna interface of the wireless radio frequency module and the common terminal of the No. 1 relay are connected to the No. 1 SMA antenna interface. The normally closed contact of the No. 1 relay is connected to the No. 2 SMA antenna interface and connected to the omnidirectional antenna. The remaining normally closed contacts of No. 2-7 relays are respectively connected to No. 3-7 SMA antenna interfaces in turn and connected to a directional antenna with a coverage of 65 degrees. The normally open contact of relay No. 1 is connected to the common terminal of relay No. 2. The normally open contact of relay No. 2 is connected to the common terminal of relay No. 3. The normally open contact of relay No. 3 is connected to the common terminal of relay No. 4. The normally open contact of relay No. 4 is connected to the common terminal of relay No. 5. The normally open contact of relay No. 5 is connected to the common terminal of relay No. 6. The normally open contact of relay No. 6 is connected to the common terminal of relay No. 7. The normally open contact of the No. 7 relay is connected to the No. 8 SMA antenna interface.

On the other hand, the present invention also provides an RSSI-based multi-antenna automatic switching method, comprising the following steps:

a. Initialize the basic configuration of the wireless radio frequency module;

b. Set the transmit power of the radio frequency module to the minimum;

c. Switch the radio frequency module antenna to an omnidirectional antenna;

d. Obtain and judge whether the RSSI value of the radio frequency module is greater than the set threshold;

e. If the RSSI value in step d is greater than the set threshold, enter the normal sending and receiving mode, and this round of work is completed. Otherwise, start to switch directional antennas in turn, and return to step d; if the RSSI value does not reach the threshold after polling all directional antennas, the radio frequency module increases the transmit power by one level. And return to step d.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, Simplifications should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (6)

1. A multi-antenna automatic switching device based on RSSI, characterized in that the device includes 1 radio frequency module, 8 SMA antenna interfaces, 7 relays, 6 directional antennas, 1 omnidirectional antenna, auxiliary power supply and a control switching circuit, the control switching circuit controls the relay to switch the radio frequency module connected to one of the directional antennas or the omnidirectional antenna through one of the eight SMA antenna interfaces. 2. according to the described a kind of RSSI-based multi-antenna automatic switching device of claim 1, it is characterized in that: in described 8 SMA antenna interfaces, No. 1 SMA antenna interface connects wireless radio frequency module antenna interface; No. 2 SMA antenna interface connects The omnidirectional antenna; the other No. 3-8 SMA antenna interfaces are connected to six directional antennas with a radiation angle of 65 degrees. 3. A kind of multi-antenna automatic switching device based on RSSI according to claim 2, it is characterized in that: described device also comprises a wireless radio frequency module antenna interface, and, the public of described wireless radio frequency module antenna interface and No. 1 relay The terminals are connected to the No. 1 SMA antenna interface; the No. 1 relay normally closed contact is connected to the No. 2 SMA antenna interface and connected to the omnidirectional antenna; the remaining No. 2-7 relay normally closed contacts are respectively connected to the No. 2-7 SMA antenna The interface is connected to a directional antenna with a launch angle of 65 degrees; the normally open contact of relay No. 1 is connected to the common terminal of relay No. 2; the normally open contact of relay No. 2 is connected to the common terminal of relay No. 3; the normally open contact of relay No. 3 is connected Connect to the public terminal of relay No. 4; the normally open contact of relay No. 4 is connected to the common terminal of relay No. 5; the normally open contact of relay No. 5 is connected to the common terminal of relay No. 6; the normally open contact of relay No. 6 is connected to the common terminal of relay No. 6 Common terminal; No. 7 relay normally open contact is connected to No. 8 SMA antenna interface. 4. An RSSI-based multi-antenna automatic switching device according to claim 3, characterized in that the device switches antennas through the relay according to the RSSI value of the radio frequency module. 5. An RSSI-based multi-antenna automatic switching device according to claim 1, wherein the auxiliary power supply is a DC 5V power supply after transformation, rectification, filtering and voltage stabilization. 6. A multi-antenna automatic switching method based on RSSI, which is used for the multi-antenna automatic switching device described in one of claims 1-5, characterized in that, comprising the following steps: a. Initialize the radio frequency module; b. Set the transmit power of the wireless radio frequency module to the minimum; c. Switching the antenna connected to the radio frequency module to the omnidirectional antenna; d. Obtain and judge whether the RSSI value of the wireless radio frequency module is greater than the set threshold; e. If the RSSI value in step d is greater than the set threshold, enter the normal transceiver mode, and this round of work is completed; otherwise, start to switch the antennas connected to the radio frequency module to directional antennas 1-6 in turn, and return to step d; if polling After finishing all directional antennas, if the RSSI value still does not reach the threshold, the radio frequency module increases the transmission power by one level, and returns to step c.