WO2015154358A1

WO2015154358A1 - Transmit diversity circuit and mobile terminal

Info

Publication number: WO2015154358A1
Application number: PCT/CN2014/084424
Authority: WO
Inventors: 谢卫博
Original assignee: 中兴通讯股份有限公司
Priority date: 2014-04-09
Filing date: 2014-08-14
Publication date: 2015-10-15
Also published as: CN104980205A

Abstract

A transmit diversity circuit and a mobile terminal used in the design of a mobile terminal antenna circuit. The transmit diversity circuit comprises: a first antenna; a second antenna; a main antenna branch; an auxiliary antenna branch; a conduction circuit one end of which is connected to the first antenna and the second antenna, and the other end of which is connected to the main antenna branch and the auxiliary antenna branch, having a first state and a second state; a control unit which is set to control the conduction circuit to switch between the first state and the second state according to a preset control strategy, wherein in the first state, the first antenna and the second antenna connect to the main antenna branch and the auxiliary antenna branch respectively through the conduction circuit, and in the second state, the first antenna and the second antenna connect to the auxiliary antenna branch and the main antenna branch and respectively through the conduction circuit. In the present invention, a terminal detects the signal strength of two antennas in real-time and always takes the antenna the electric field position of which is better as the transmit antenna, to enhance the data transmission capability of the communication terminal uplink and meanwhile to reduce the power consumption of the terminal device.

Description

Transmit diversity circuit and mobile terminal

Technical field

The present invention relates to the field of transmit diversity techniques, and more particularly to a transmit diversity circuit and a mobile terminal.

Background technique

In the related art, the mobile terminal circuit in the FDD (Frequency Division Duplexing) working mode mainly includes a transmitting branch, a primary receiving branch, and a diversity receiving diversity circuit, wherein the transmitting branch and the primary receiving branch pass through the dual The unit is combined into a common path that is connected to the main path antenna. The diversity receive branch is a relatively independent circuit that is connected to the diversity antenna.

The physical meaning of diversity reception includes enabling the receiving end to obtain a plurality of statistically independent fading signals carrying the same information, and combining the received plurality of statistically independent fading signals to reduce the influence of spatial fading on the received signal.

In hardware design, in order to improve the isolation between the primary and secondary antennas, the minimum distance and direction between the primary and secondary antennas are strictly required. Generally, the primary and secondary antennas are designed at both ends of the terminal, The isolation is the biggest.

Figure 1 shows the traditional circuit design.

When the communication terminal works, due to the power closed-loop control requirement, when the terminal detects that the received signal is weak, in order to ensure the balance of the communication link, the terminal will increase the transmission power of the transmitter to ensure the balance of the communication link. In practical applications, because the primary and secondary antennas are in different positions in the electric field of the base station, the strength of the signals received by the two antennas will be different.

Figure 2 Schematic diagram of the location of the terminal antenna in the electric field of the base station.

In some cases, the antenna 1 receives a signal that is stronger than the signal received by the antenna 2, and the antenna 1 is at an unfavorable position relative to the antenna 2 in the base station electric field. At this time, when the antenna 1 uses the antenna 1 to transmit uplink data, the order of the data modulation is reduced, and the uplink rate of the terminal is lowered. At the same time, according to the power closed-loop control mechanism, the terminal increases the transmission power, which may cause the terminal power consumption to increase. Therefore, there is a problem in the related art due to the antenna being in an unfavorable position in the electric field of the base station. The problem of the lower uplink rate is reduced.

Summary of the invention

The technical problem to be solved by the embodiments of the present invention is to provide a transmit diversity circuit and a mobile terminal including the same, to solve the problem that the uplink rate of the terminal is reduced due to the antenna being in an unfavorable position in the electric field of the base station. problem.

In order to achieve the above objectives, the following technical solutions are used:

A transmit diversity circuit includes: a first antenna, a second antenna, a main antenna branch, a secondary antenna branch, a conduction circuit, and a control unit, where:

One end of the conducting circuit is connected to the first antenna and the second antenna, and the other end is connected to the main antenna branch and the auxiliary antenna branch, and has a first state and a second state;

The control unit is configured to: control the conduction circuit to switch between the first state and the second state according to a preset control policy;

In the first state, the first antenna is connected to the main antenna branch through the conductive circuit, and the second antenna is connected to the auxiliary antenna branch through the conductive circuit; In the second state, the first antenna is connected to the auxiliary antenna branch through the conduction circuit, and the second antenna is connected to the main antenna branch through the conduction circuit.

Optionally, the main antenna branch includes: a transmitting branch, a main receiving branch, and a duplexer, where: the transmitting branch is connected to a radio frequency chip of the terminal;

The primary receiving branch is also connected to the radio frequency chip of the terminal;

The duplexer is connected to the conducting circuit, and the duplexer is configured to: merge the transmitting branch with the main receiving branch.

Optionally, the auxiliary antenna branch is a diversity receiving branch.

Optionally, the control unit is further configured to:

Obtaining a first signal strength corresponding to the first antenna and a second signal strength corresponding to the second antenna, and comparing the first signal strength with the second signal strength in real time.

Optionally, the preset control policy includes: Controlling, when the value of the first signal strength is greater than the value of the second signal strength, exceeds a preset threshold for a preset duration, the first antenna and the main antenna branch are turned on, and the second antenna is The auxiliary antenna branch is turned on;

Controlling, when the second signal strength is greater than the value of the first signal strength, exceeds the preset threshold for the preset duration, the second antenna and the main antenna branch are turned on, and simultaneously The first antenna is electrically connected to the auxiliary antenna branch.

Optionally, the preset threshold is ldB.

Optionally, the preset duration is 1 second.

Optionally, the conducting circuit is a double pole double throw switch.

Optionally, the control unit is a baseband chip.

A mobile terminal comprising any of the transmit diversity circuits described above.

The above technical solution detects the signal strength of two antennas in real time through the terminal, and always uses the antenna with a better electric field position as the transmitting antenna, and limits the threshold of the switching, reduces the number of invalid switching of the switch, and enhances the interference of the switch by external interference. ability. Effectively improve the uplink rate of the terminal, and appropriately reduce the transmit power of the power amplifier of the terminal, reducing the power consumption of the whole machine, and effectively extending the battery life time for the terminal product with the battery. BRIEF abstract

The drawings are intended to provide a further understanding of the present invention, and are intended to be a part of the present invention, and the description of the present invention and the description thereof are not intended to limit the invention. In the drawing:

1 is a schematic structural view of a conventional transmit diversity circuit according to the background art of the present invention; FIG. 2 is a schematic diagram showing the position of a terminal antenna in an electric field of a base station according to the background art of the present invention; FIG. 3 is a view showing the transmission according to the first embodiment of the present invention; Schematic diagram of the diversity circuit;

4 is a flow chart showing an example of a preset control strategy according to Embodiment 1 of the present invention; FIG. 5 is a flow chart showing a second example of the preset control strategy according to the first embodiment of the present invention; FIG. 6 is a flowchart showing a third example of the preset control strategy according to the first embodiment of the present invention; A schematic diagram of the structure of the transmit diversity circuit. Preferred embodiment of the invention

The embodiments of the present invention are described in detail below with reference to the accompanying drawings, but the invention may be embodied in many different ways as defined and covered by the appended claims.

Embodiment 1

FIG. 3 is a schematic structural diagram of a transmit diversity circuit according to Embodiment 1 of the present invention.

Referring to FIG. 3, the transmit diversity circuit includes: a first antenna 10, a second antenna 20, a main antenna branch 4, a secondary antenna branch 5, a conduction circuit 3, and a control unit 6, wherein:

The conducting circuit 3 is connected to the first antenna 10 and the second antenna 20, respectively, and the conducting circuit 3 has a first state and a second state;

The control unit 6 is configured to control the conduction circuit 3 to switch between the first state and the second state according to a preset control policy;

In the first state, the first antenna 10 and the second antenna 20 are respectively connected to the main antenna branch 4 and the auxiliary antenna branch 5 through the conduction circuit 3, that is, the first An antenna 10 is connected to the main antenna branch 4, and a second antenna 20 is connected to the auxiliary antenna branch 5. In the second state, the first antenna 10 and the second antenna 20 pass through the conduction circuit 3. The auxiliary antenna branch 4 and the main antenna branch 5 are respectively connected, that is, the first antenna 10 is connected to the auxiliary antenna branch 5, and the second antenna 20 is connected to the main antenna branch 4.

In the above technical solution of the embodiment, two antennas with equal or close performance, that is, the first antenna 10 and the second antenna 20 are required in the transmit diversity circuit. The main antenna branch 4 is the main receiving branch, and the auxiliary antenna branch 5 is the diversity receiving branch. The conducting circuit 3 is connected to the main antenna branch 4 according to the preset control strategy of the control unit 6. The second antenna 20 can also be switched between the main antenna branch 4 and the auxiliary antenna branch 5, and the effect achieved is that in practical applications, due to the main The position of the auxiliary antenna in the electric field of the base station is different, and the strength of the signals received by the two antennas may be different. In some cases, the first antenna 10 The received signal will be stronger than the signal received by the second antenna 20, while the first antenna 10 is at an unfavorable position relative to the second antenna 20 in the base station electric field. Therefore, when the terminal uses the first antenna 10 to transmit uplink data, the terminal reduces the order of data modulation, which causes the uplink rate of the terminal to decrease. At the same time, according to the power closed-loop control mechanism, the terminal increases the transmit power, which may result in power consumption of the terminal. increase. With the above technical solution of the present embodiment, when the above situation occurs, the control unit 6 controls the conduction circuit 3 according to the preset control policy, so that the first antenna 10 and the second antenna 20 respectively and the main antenna When the branch 4 and the auxiliary antenna branch 5 are switched on, the transmission power can be improved and the power consumption can be reduced.

Optionally, the foregoing preset control policy includes: controlling the first antenna 10 and the main antenna branch when the first signal strength is greater than the value of the second signal strength exceeds a preset threshold for a preset duration The second antenna 20 is electrically connected to the auxiliary antenna branch 5; and the second signal strength is greater than the value of the first signal strength exceeding the preset threshold for the preset duration The second antenna 5 is controlled to be electrically connected to the main antenna branch 4, and the first antenna and the auxiliary antenna branch 5 are electrically connected.

The working process of the transmit diversity circuit of the present invention will be exemplified below, and the preset control strategy will be specifically explained.

Case 1: As shown in Figure 4, the working process of the transmit diversity circuit includes:

Step 401: The default transmitting antenna is the main antenna 1.

First, at power-on initialization, the system defaults to antenna 1 of the two antennas as the transmitting antenna, and uses the uplink signal transmitted by antenna 1 to interact with the wireless communication network.

Step 402: Process the signals received by the two antennas separately, and detect the RSSI1 and RSSI2 signals.

After accessing the network, the terminal processes the radio frequency signals received by the two antennas, and demodulates the signal strengths RSSI1 and RSSI2 of the two.

Step 403: Compare the sizes of RSSI1 and RSSI2.

If the RSSI1 is greater than the RSSI2, it indicates that the transmitting antenna meets the working requirement, and the switch does not perform the action, and returns to step 403. If the RSSI2 is greater than the RSSI1, the current transmitting antenna does not meet the working requirement, and the switching execution step 404 is required.

Step 404: The control unit outputs a control command, and the switch is switched. Step 405: The transmitting antenna is switched to the antenna 2.

That is, the baseband chip issues a switching command, the switching switch performs a switching action, and the transmitting antenna switches to the antenna 2. In order to reduce unnecessary switching, it is necessary to ensure that RSSI2 is greater than RSSI1 ldB and keep it for 1 second, which will reduce the number of invalid switching of the switch and reduce the misoperation caused by external interference.

Step 406: Compare the sizes of RSSI1 and RSSI2.

As the location of the terminal changes in the wireless network, starting from a certain location, the terminal detects that RSSI1 is greater than RSSI2, indicating that the current transmitting antenna does not meet the working requirements and needs to be switched.

Step 407: The control unit outputs a control command, and the switch is switched.

Step 408: Switch the world to the antenna 1 .

Then, the baseband chip issues a switching instruction, the switching switch performs a switching action, and the transmitting antenna switches to the antenna 1. In order to reduce unnecessary switching, it is necessary to ensure that RSSI1 is greater than RSSI2 ldB and keep it for 1 second, which will reduce the number of invalid switching of the switch and reduce the misoperation caused by external interference.

Case 2: Referring to Figure 5, the working process of the transmit diversity circuit includes:

Step 501: The default transmitting antenna is the main antenna 1.

First, at power-on initialization, the system defaults to antenna 2 of the two antennas as the transmitting antenna, and uses the uplink signal transmitted by antenna 2 to interact with the wireless communication network.

Step 502: Process the signals received by the two antennas separately, and detect the RSSI1 and RSSI2 signals.

Step 503: Compare the sizes of RSSI1 and RSSI2.

If RSSI1 is greater than RSSI2, it means that the current transmitting antenna does not meet the working requirements and needs to be switched.

Step 504: The control unit outputs a control command, and the switch is switched.

Step 505: The transmitting antenna is switched to the antenna 2. That is, the baseband chip issues a switching command, the switching switch performs a switching operation, and the transmitting antenna switches to the antenna 1. In order to reduce unnecessary switching, it is necessary to ensure that RSSI1 is greater than RSSI2 1dB and keep it for 1 second, which will reduce the number of invalid switching of the switch and reduce the misoperation caused by external interference.

Step 506: Compare the sizes of RSSI1 and RSSI2.

When RSSI2 is greater than RSSI1, step 506 is returned. The RSSI1 is greater than the RSSI2 Id B and remains for 1 second, and step 507 is performed.

Step 507: The control unit outputs a control command, and the switch is switched.

Step 508: The transmitting antenna is switched to the antenna 1.

As the location of the terminal changes in the wireless network, the terminal detects that RSSI2 is greater than RSSI1 from a certain location, indicating that the current transmitting antenna does not meet the working requirements, and needs to be switched. Then the baseband chip issues a switching instruction, and the switching switch makes a switching action. , the transmit antenna is switched to antenna 2. In order to reduce unnecessary switching, it is necessary to ensure that RSSI2 is greater than RSSI1 IdB and keep it for 1 second, which will reduce the number of invalid switching of the switch and reduce the misoperation caused by external interference.

Case 3: Referring to Figure 6, the working process of the transmit diversity circuit includes:

Step 601: In the initial state, the two antennas only receive the downlink signal of the base station.

Step 602: Process the signals received by the two antennas separately, and detect RSSI1 and RSSI2. First, during power-on initialization, the system only receives the downlink signal of the base station, and does not transmit the signal output. The terminal processes the radio frequency signals received by the two antennas, and demodulates the signal strengths RSSI1 and RSSI2 of the two antennas respectively.

Step 603: Compare the sizes of RSSI1 and RSSI2.

If RSSI1 is greater than RSSI2, indicating that the transmitting antenna 1 meets the working requirements, the antenna 1 is used as the return to step 603.

As the location of the terminal in the wireless network changes, the terminal detects that the RSSI2 is greater than the RSSI1 from a certain location, indicating that the current transmitting antenna does not meet the working requirements, and the handover is required, and step 604 is performed.

Step 604: The control unit outputs a control command, and the switch is switched. Step 605: The transmitting antenna is switched to the antenna 1.

Step 606: Align the sizes of RSSI2 and RSSI1.

The terminal detects that the RSSI1 is greater than the RSSI2, indicating that the current transmitting antenna does not meet the working requirements, and needs to perform the handover, and step 607 is performed.

Step 607: The control unit outputs a control command, and the switch is switched.

Step 608: The transmitting antenna is switched to the antenna 2.

That is, the baseband chip issues a switching command, the switching switch performs a switching action, and the transmitting antenna switches to the antenna 2. In order to reduce unnecessary switching, it is necessary to ensure that RSSI1 is greater than 1 dB of RSSI2 and keep it for 1 second, which will reduce the number of invalid switching of the switch and reduce the misoperation caused by external interference.

In the above embodiment, the signal strength of the two antennas is detected in real time by the terminal, and the antenna with better electric field position is always used as the transmitting antenna, and the threshold of the switching is limited, the number of invalid switching of the switch is reduced, and the switch is enhanced by external interference. ability. Effectively increase the terminal's uplink rate, and appropriately reduce the terminal's power amplifier's transmit power, reducing the power consumption of the whole machine, and effectively extend the battery life time for battery-equipped terminal products.

Embodiment 2

FIG. 7 is a schematic structural diagram of a transmit diversity circuit according to Embodiment 2 of the present invention.

Referring to FIG. 7, the transmit diversity circuit includes: an antenna with equal or close performance, an antenna 1 and an antenna 2, a transmit branch PA configured to transmit a signal for outputting a radio frequency signal, and a main receive branch LNA configured to receive an antenna for reception. The main path to the receiving signal; the transmitting and receiving duplexers are arranged to combine the transmitting branch and the main receiving branch into one common path; the diversity receiving branch, that is, the auxiliary path LNA, is set to receive the diversity reception received by the receiving antenna Signal; an X-type double-pole double-throw DPDT switch, that is, the conduction circuit 3, is set to switch the transmission path and the connection of the antenna 1 and the antenna 2; the baseband chip in the circuit, that is, the above-mentioned control unit 4, is set to control X Switching of double-pole double-throw DPDT switch Action.

The signal strengths RSSI1 and RSSI2 received by antenna 1 and antenna 2 are demodulated inside the radio chip of the communication terminal, and an algorithm of the internal software of the baseband chip is used to compare the signal strengths of the two signals to determine an antenna with strong received signal strength. .

Through the control logic algorithm, the switching command of the X-type double-pole double-throw DPDT switch is controlled to ensure that the transmitting channel can be switched to the antenna with better received signal strength.

The mobile terminal provided by the embodiment of the present invention uses the following technical solutions:

The mobile terminal includes the above-described transmit diversity circuit.

The invention detects the signal strength of two antennas in real time through the terminal, and always uses the antenna with better electric field position as the transmitting antenna, and limits the threshold of the switching of the switch, reduces the number of invalid switching of the switch, and enhances the ability of the switch to be interfered by the outside world. . Effectively improve the uplink rate of the terminal, and appropriately reduce the transmission power of the power amplifier of the terminal, thereby reducing the power consumption of the whole machine, and effectively extending the battery life time for the terminal product with the battery.

The above is a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. It should be considered as the scope of protection of the present invention.

Industrial applicability

The above technical solution detects the signal strength of two antennas in real time through the terminal, and always uses the antenna with a better electric field position as the transmitting antenna, and limits the threshold of the switching, reduces the number of invalid switching of the switch, and enhances the interference of the switch by external interference. ability. Effectively improve the uplink rate of the terminal, and appropriately reduce the transmit power of the power amplifier of the terminal, reducing the power consumption of the whole machine, and effectively extending the battery life time for the terminal product with the battery. Therefore, the present invention has strong industrial applicability.

Claims

Claim

A transmit diversity circuit comprising: a first antenna, a second antenna, a main antenna branch, an auxiliary antenna branch, a conduction circuit, and a control unit, wherein:

The transmit diversity circuit according to claim 1, wherein the main antenna branch comprises: a transmit branch, a main receive branch, and a duplexer, where:

The transmitting branch is connected to the radio frequency chip of the terminal;

3. The transmit diversity circuit of claim 2, wherein the secondary antenna branch is a diversity receive branch.

The transmit diversity circuit according to any one of claims 1 to 3, wherein the control unit is further configured to:

The transmit diversity circuit according to claim 4, wherein the preset control strategy comprises: when the value of the first signal strength is greater than a preset threshold value by a preset duration; Controlling, the first antenna and the main antenna branch are turned on, and the second antenna and the auxiliary antenna branch are conducting; Controlling, when the second signal strength is greater than the value of the first signal strength, exceeds the preset threshold for the preset duration, the second antenna and the main antenna branch are turned on, and simultaneously The first antenna is electrically connected to the auxiliary antenna branch.

6. The transmit diversity circuit of claim 5, wherein the predetermined threshold is ldB.

7. The transmit diversity circuit according to claim 6, wherein the preset duration is 1 second.

8. The transmit diversity circuit of claim 1, wherein the conductive circuit is a double pole double throw switch.

The transmit diversity circuit according to claim 8, wherein the control unit is a baseband chip.

10. A mobile terminal comprising the transmit diversity circuit of any one of claims 1-9.