WO2008052449A1

WO2008052449A1 - Method and apparatus for simplifying the rf front end

Info

Publication number: WO2008052449A1
Application number: PCT/CN2007/070345
Authority: WO
Inventors: Xiaohong Chen; Tao Pu
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-11-03
Filing date: 2007-07-24
Publication date: 2008-05-08
Also published as: CN100557990C; CN1980072A

Abstract

A method and apparatus for simplifying the radio frequency (RF) front end. Comparing with the prior mobile communication outdoor device, the number of the resonator cavity in the receiving filter and the transmitting filter of the RF front end is reduced to realize the purpose of decreasing the volume and the weight of the whole RF front end. The filtering effect of the filter will be decreased after the above change. The problem can be solved through adding on-board installable filter and low noise amplifier.

Description

Simplified method and device for RF front end This application claims priority to Chinese patent application filed on November 3, 2006, the Chinese Patent Office, Application No. 200610063502.4, entitled "Simplified Method and Apparatus for RF Front End" The entire contents of which are incorporated herein by reference. Technical field

The present invention relates to the field of wireless communication technologies, and in particular, to a simplified method and apparatus for a radio frequency front end. Background technique

In the field of mobile communications, operators have used a large number of outdoor base stations, radio remote modules, and repeaters to avoid building a computer room. On the one hand, for the convenience of installation and maintenance, the size and weight of these outdoor equipments are strictly required; on the other hand, in the case of a fixed volume, in order to ensure reliability, there is sufficient space inside the equipment for the equipment. Reliability design, such as heat dissipation. As shown in Fig. 1, the system structure diagram for filtering in the prior art using the RF cavity filter can be seen from the figure, the signal needs to pass through the RF cavity filter before input or output. The filter and the transmit filter 30 are received, and the filtered received signal is amplified by the amplifier 10 and sent to the receiver. The signal from the transmitter is amplified by the amplifier 20, sent to the transmit filter, filtered, and transmitted through the antenna. Inside such devices, both the receive filter and the transmit filter 30 require a RF cavity filter as the filter, and such filters typically consist of 8 to 9 filter resonator cavities. It is used to suppress the signal outside the communication band (hereinafter referred to as out-of-band) and play a filtering role. The power of the transmitted signal is generally large, and only the cavity filter can withstand such a high-powered transmit signal without damage. However, the volume and weight of such a cavity filter occupies a considerable amount in the internal module of the device. The proportion, especially in the lower communication bands (such as GSM900, CDMA850), is even larger.

In summary, the RF front end of these outdoor devices includes a RF cavity filter. Such a filter can meet the overall power capacity and transceiver isolation requirements of outdoor equipment, but the size and weight of such a filter occupies a considerable proportion in the internal modules of the outdoor equipment, especially in the lower communication frequency band. More huge. The RF front end of the prior art mobile communication outdoor equipment is bulky, heavy, poor in reliability, high in production cost, and low in competitiveness. Summary of the invention

The present invention provides a simplified method and apparatus for a radio frequency front end for reducing the volume and weight of an RF front end.

The present invention provides a simplified method of a radio frequency front end, including:

The signal received by the antenna is filtered by a simplified receive filter;

The signal filtered by the simplified receiving filter is re-filtered by a single-board mounted filter; the signal filtered by the single-board mounted filter is amplified by an amplifier.

Another simplified method of the RF front end provided by the present invention includes:

Amplifying the signal that needs to be transmitted through an amplifier;

The signal amplified by the amplifier is filtered by a single board mounted filter;

The filtered signal of the single-board mounted filter is sent to the power amplifier for amplification; the amplified signal of the power amplifier is sent to the simplified transmit filter for re-filtering.

The present invention provides a radio frequency front end device, including: a simplified filtering unit, a filtering amplifying unit; the simplified filtering unit includes at least one simplified filter, the simplified filter having at least one resonant cavity;

The filter amplifying unit is composed of a single board mounted filter and an amplifier.

The method and device introduced in the present invention can simplify the volume and weight of the RF front end, and the simplified RF front end can use different degrees of simplified front end methods to meet different spaces according to the requirements for suppression of out-of-band signals. The condition is limited, and at the same time, the optimal RF performance is not required in practical use, but the technical solution is provided when the volume requirement of the RF filtering device is sensitive. DRAWINGS

1 is a schematic diagram of a system of a radio frequency front end provided in the prior art;

2 is a flow chart of a simplified RF front-end method provided by the present invention;

3 is a schematic structural diagram of a simplified radio frequency front end device provided by the present invention;

4 is a schematic block diagram showing the structure of a simplified radio frequency front end device provided by the present invention;

FIG. 5 is a schematic diagram showing the structure of a simplified radio frequency front end device provided by the present invention. detailed description

The invention provides a design method of a radio frequency front end and a device manufactured by the method To make up for the shortcomings of the prior art, in order to achieve the purpose of manufacturing a mobile communication outdoor device that is small in size, light in weight, high in reliability, and low in cost.

The embodiment of the invention provides a design method for a radio frequency front end of a single-side reduced mobile communication outdoor device, which simplifies the volume and weight of the receiving filter in the duplexer and increases other small-sized single board-mounted filtering. In order to ensure that the indicators of the whole machine are unchanged. The volume and weight of the receiving filter in the simplified duplexer can be realized by reducing the number of receiving filter resonators. The specific operation flow is shown in Figure 2, including:

Step 201: The mobile communication outdoor device receiving antenna receives the wireless communication signal.

Step 202: The antenna sends the received wireless communication signal to a simplified receiving filter, and the simplified receiving filter performs preliminary filtering on the received communication signal.

Step 203: The initially filtered wireless communication signal is sent to a technical filter, specifically, a single board mounted filter for re-filtering;

Step 204: The wireless communication signal filtered by the single board mounted filter is sent to a low noise amplifier (LNA) signal amplifying unit for signal amplification.

The LNA signal amplification is significantly different from the LNA signal amplification in the prior art. The main reason is that the LNA signal amplification in this embodiment does not directly directly amplify the signal filtered by the front end, but adds technology before the signal amplification. The filter (ie, the single-board mounted filter) filtering step, in step 203, the received signal is different from the prior art signal, but is a signal that is initially filtered. If it is directly amplified, the out-of-band signal of strong power will also be amplified together. Therefore, the LNA in the embodiment of the present invention adds a single board mounted filter. The technical filter, that is, the single-board mounted filter, may be a dielectric filter or an RF surface acoustic wave filter. Both types of filters are very small in size and low in cost, and after the initial filtering, the amplitude is still The larger signal is re-filtered and sent to the LNA for signal amplification. If the out-of-band signal amplified by the LNA has been suppressed to a lower amplitude, it can be directly output to the receiver for normal delivery. If the amplitude of the amplified out-of-band signal is still large, secondary board filtering can also be performed for the out-of-band signal. The above steps can be performed multiple times according to the actual situation, and the need for out-of-band signal suppression is required until it meets the requirements.

In actual use, the signal obtained by the secondary single-board filtering and the secondary LNA signal amplification is substantially the same as that obtained in the prior art without using the reduced RF front-end design method. By the same token, in this embodiment, the method of simplifying the RF front end can also be applied to the transmitting filter end. If the simplified filtering method is used in the transmitting filter end, a small size should be added before the transmitting front end filter is simplified. The board-mounted filter is subjected to corresponding signal amplification to meet the transmit power requirements of the transmitted signal. The number of times of board-mounted filtering and signal amplification is determined by the simplification of the simplified filter and the final requirements for the transmitted signal. Because the specific implementation method is similar to the embodiment, the pre-filtered signal is re-filtered by using a single-board mounted filter, and the re-filtered signal is amplified by the signal amplifier, so as to obtain the prior art. There is no filter signal that uses the same signal to reduce the RF front-end design method to meet the overall requirements of the signal.

Another embodiment of the present invention provides another method for designing a radio frequency front end of a single-side reduced mobile communication outdoor device. In order to improve the sensitivity performance of the receiver, the receiving filter in the duplexer is simplified, and therefore, the filter is required to be reduced. Under the condition of volume and weight, the single-board mounted filter before the first-stage LNA is removed, and the filtering performance of the subsequent-stage single-board filter is improved. When using this method, the simplification of the simplified filter is not the simplest state, but the amplitude of the out-of-band signal that the filtered LNA can withstand is used as a simplification basis.

Compared with the front end in the simplest state, the volume and quality of the simplified front end are increased to improve the suppression of the out-of-band signal and reduce the amplitude of the out-of-band signal at the LNA input.

When using this method, since the simplified receiving filter does not reach the maximum, the filtered signal generally does not need to be filtered by the two-stage single-board filter, but only the preliminary filtered signal is sent directly to the LNA after amplification. After a single board-mounted filter filtering and LNA amplification, the requirements for out-of-band signal suppression can be satisfied, and the filtered signal obtained by the method in this embodiment is closer to the prior art. The signal obtained when the filter structure.

Another embodiment provided by the present invention is a method for designing a radio frequency front end of a dual-side mobile communication outdoor device, which is simplified in the receiving filter side and is the same simplification in the first two embodiments of the present invention. The method uses a simplified primary filter to filter the primary filtered signal through a combination of a single-board mounted filter and an LNA amplifier to achieve the purpose of simplifying the RF front-end transmitting side, and at the same time filtering the signal quality. Does not cause functional impact. A simplified method of its transmitting end side includes:

Adding a filter at the end of the transmitter to reduce spurious signals in the signal from the transmitter, The filter may be a single-board mounted filter; after filtering by the filter, the signal is sent to a power amplifier for power amplification, and the power amplified signal is sent to a cavity filter capable of withstanding a high power signal; The signal has been filtered before amplification, so the same filtering effect can be achieved with a smaller volume of the cavity filter. In this embodiment, a simplified transmit filter is used to reduce the front side of the transmitting side. RF end volume and weight.

In this embodiment, the filter can also use the same multi-stage filtering amplification method as in the previous embodiment to achieve the maximum reduction in volume and weight of the transmission filter. Therefore, in practical applications, different schemes can be used depending on the emphasis on system simplification and filtering effects.

A further embodiment provided by the present invention is a device for reducing the radio frequency front end of a mobile communication outdoor device on one side, which comprises a simplified input filter, at least one level of a single board mounted filter and an LNA amplifier, wherein The block diagram of the single-board mounted filter and the two-stage LNA amplifier is shown in Figure 3. It includes: a simplified receive filter 31, two-stage single-board mounted filters 11, 13 and a two-stage LNA amplifier 12. 14; The specific block diagram of the first-level single-board mounted filter and the two-stage LNA amplifier is shown in Figure 4. The structure of the simplified receiving filter in this embodiment is the same as that of the receiving filter in the prior art, but the number of resonant cavities is greatly reduced, and the filtering effect of the signal after the number of resonant cavities is reduced is worse than that of the prior art. More grades of single-board mounted filters are filtered with the LNA, and the minimum number of resonant cavities can be reduced to only one, thereby reducing the volume and weight of the receiving filter; the number of stages used in the board-mounted filter The simplified filter in the front section is related to the suppression of out-of-band signals. The more simplified the suppression of the filter, the more stages the single-board mounted filter requires.

Similarly, the device described in this embodiment can also be used separately at the transmitting end, and its specific structure is similar to that of the receiving side. It also uses a simplified front-end matching single-board mounted filter and amplifier through a single-board mounted filter. The combination with the amplifier to achieve the filtering effect on the transmitted signal, the filtering of the transmitted signal can be realized only by the filter with simple structure, and the application of the simple filter is simplified. The purpose of the RF front end is to simplify the transmitting side.

Another embodiment provided by the present invention is a device for reducing the radio frequency front end of a mobile communication outdoor device on both sides. By using the combination and operation of the device structure introduced in the previous embodiments, a simplified filter is used simultaneously on the receiving side and the transmitting side. Combined with a single board mounted filter and LNA, the specific knot The block diagram is shown in FIG. 5, wherein the simplified transmit filter 33 reduces the spurious signals of the transmitter by adding a primary filter at the end of the transmitter 40 module, and also reduces the duplexer 30 module. The suppression of the transmitter filter 32 is required to reduce the size of the duplexer. By using a simplified filter structure on both sides of the receiving and transmitting sides and in combination with a single board mounted filter and amplifier, the object of reducing the volume and weight of the device can be better achieved, according to the first few embodiments of the present invention. The description can be obtained that the device for narrowing the RF front end of the mobile communication device can also use a two-stage single-board type filter to realize the purpose of simplifying the filter structure by combining the first-stage amplifiers. The structure of the filter can also be achieved using a combination of at least one stage single board mounted filter with at least one stage amplifier to achieve a simplified double side filter structure.

In the above embodiments, the method and apparatus for simplifying filtering on the transmitting side differs from the method and apparatus for simplifying the selection of the amplifier and the receiving side. The amplifier selected on the transmitting side can be an ordinary amplifier or an LNA amplifier. The spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and modifications of the invention

Claims

Rights request

A simplified method for an RF front end, comprising:

The signal received by the antenna is filtered by a simplified receive filter;

2. The method of claim 1 wherein the simplified receive filter is a cavity filter comprising at least one resonant cavity.

3. The method according to claim 1, wherein the simplified receiving filter is a filter that reduces d, a large cavity d, and a number of filters.

4. The method according to claim 1, wherein the single board mounted filter is a dielectric filter or a radio frequency surface acoustic wave filter.

5. The method of claim 1 wherein the amplifier is a low noise amplifier LNA.

6. A simplified method of an RF front end, characterized by comprising:

Amplifying the signal that needs to be transmitted through an amplifier;

7. The method of claim 6 wherein the simplified transmit filter is a filter comprising at least one resonant cavity.

8. The method according to claim 6, wherein the cavity of the simplified transmission filter has a large d, and the number is adjustable.

9. The method according to claim 6, wherein the single board mounted filter is a dielectric filter or a radio frequency surface acoustic wave filter.

10. An RF front-end device, comprising: a simplified filtering unit and a filtering and amplifying unit;

The simplified filtering unit includes at least one simplified filter having at least one resonant cavity;

The filter amplification unit includes a single board mounted filter and an amplifier.

11. Apparatus according to claim 10 wherein the resonant cavity of the simplified filter is large in number and adjustable in number.

12. The apparatus according to claim 10, wherein the filter amplifying unit comprises at least one single board mounted filter and an amplifier group.

13. The apparatus according to claim 10, wherein the single board mounted filter in the filter amplifying unit is a dielectric filter or a radio frequency surface acoustic wave filter.

14. Apparatus according to claim 10 wherein the amplifier in the filter amplification unit is an LNA amplifier.