CN1702988A - Method for implementing uplink and downlink switching of TD-SCDMA repeater - Google Patents

Abstract

The invention relates to a method for controlling uplink and downlink switching by a time division synchronous code division multiple access repeater. The link transmits the information to the calculation and control module; the calculation and control module uses the satellite positioning receiver to obtain the position information and standard time of the repeater, and the calculation and control module calculates the distance between the base station and the repeater based on the position information of the base station and the repeater. The radio wave transmission delay between the base station and the repeater, and then calculate the precise repeater switching point time according to the radio wave transmission delay between the base station and the repeater and the time information of the two switching points, and generate a control signal to control the repeater The radio frequency link performs uplink and downlink switching. The method has the characteristics of high reliability and simplicity, and eliminates the influence of radio wave transmission on the timing accuracy of extracting switching points by repeaters.

Description

A Method for Realizing Uplink and Downlink Switching in Time Division Synchronous Code Division Multiple Access Repeater

Technical field

The invention relates to a method for realizing uplink and downlink switching of a time division synchronous code division multiple access TD-SCDMA repeater.

Background technique

TD-SCDMA is one of the third-generation mobile communication air interface technical specifications officially released by the International Telecommunication Union ITU. Its key technologies include time-division duplex technology with adjustable uplink and downlink switching points, smart antenna technology, and joint detection technology. The advantages of TD-SCDMA are highlighted in the good balance between system anti-interference and system capacity, efficient support for mixed services, and the system itself has good continuous development and technological evolution.

The multiple access scheme of TD-SCDMA belongs to DS-SCDMA, the chip rate is 1.28Mc/s, the spread spectrum bandwidth is about 1.6MHz, and it adopts the TDD working mode without matching frequency. Its downlink and uplink information are transmitted on different time slots of the same carrier frequency. The physical channel of TD-SCDMA adopts four-layer structure: system frame, wireless frame, subframe and time slot/code. Fig. 1 is the physical channel signal format of TD-SCDMA. Its frame structure divides the 10ms wireless frame into two 5ms subframes, and each subframe has 7 regular time slots and 3 special time slots. The three special time slots are downlink pilot time slot DwPTS, main guard time slot GP and uplink pilot time slot UpPTS. TS ₀ is always allocated to the downlink and TS ₁ is always allocated to the uplink in the 7 regular time slots. By flexibly configuring the number of uplink and downlink time slots, TD-SCDMA is suitable for uplink and downlink symmetric and asymmetric business modes. Uplink time slots and downlink time slots are separated by switching points. In the TD-SCDMA system, each 5ms subframe has two transition points: the first transition point is from the downlink to the uplink, the GP between DwPTS and UpPTS; the second transition point It is from the uplink to the downlink, the position is between the last uplink time slot and the second downlink time slot in each subframe, and TS ₀ is the first downlink time slot. Wherein, the first conversion point is fixed with respect to the start time of each subframe; the second conversion point varies with the number of time slots allocated to the uplink and downlink.

No matter what kind of wireless communication coverage area will produce weak signal areas and blind areas, and for some remote areas and blind areas with a small number of users, the cost of setting up base stations is too high, and the infrastructure is also relatively complicated. To provide a low-cost , Simple to set up, but economical and effective equipment with the function of a small base station---repeater is very necessary. Therefore, TD-SCDMA repeater plays an important role in TD-SCDMA network.

In the TD-SCDMA system, the uplink signal and the downlink signal are at the same frequency, and the uplink and downlink are distinguished by time division multiplexing. Therefore, the TD-SCDMA repeater needs to obtain the position information of two switching points to realize the uplink and downlink switching of radio frequency channels.

Existing methods for obtaining the first conversion point include: feature window search method and downlink synchronization code correlation method. Existing feature window search methods are prone to misjudgment due to interference from user terminals or adjacent base stations. The principle of the downlink synchronization code correlation method is not easily disturbed, but its technical complexity is high, and it is not easy for repeater manufacturers to realize it.

Someone proposes to obtain the second conversion point by broadcasting the time information of the second conversion point in the TD-SCDMA broadcast channel. This method has the following two problems: 1. Modify the existing TD-SCDMA protocol; 2. High technical complexity.

Contents of the invention

The purpose of the present invention is to overcome the defects or problems in the above-mentioned prior art, and provide a highly reliable and simple method for obtaining two switching points of the TD-SCDMA system and realizing the uplink and downlink switching of the repeater.

The method comprises the steps of:

a. The control center obtains the location information of the base station and the time information of two switching points from the wireless network controller or the base station;

b. The control center uses the communication link to transmit the base station location information and the time information of the two conversion points to the calculation and control module;

c. The calculation and control module uses the satellite positioning receiver to obtain the position information and standard time of the repeater;

d. The calculation and control module calculates the radio wave transmission delay between the base station and the repeater according to the position information of the base station and the repeater;

e. The calculation and control module calculates the precise time of the repeater conversion point according to the radio wave transmission delay between the base station and the repeater and the time information of the two conversion points, and generates a control signal to control the radio frequency link of the repeater Perform uplink and downlink switching.

When the position of the base station or the time information of the two conversion points are adjusted, the above steps a to e are repeated.

The invention utilizes the communication link to transmit the position information of the base station and the time information of two conversion points, and the information is updated dynamically.

Realize repeater control uplink and downlink switching system, including: control center, communication link and repeater, repeater is equipped with calculation and control module, satellite positioning receiver, repeater radio frequency link, control center will base station location The information and the time information of two conversion points are transmitted to the repeater through the communication link; the satellite positioning receiver transmits the acquired position information and standard time of the repeater to the calculation and control module; the calculation and control module calculates the radio wave transmission Time delay and the position of the two switching points of the repeater, and control the radio frequency link of the repeater to switch between uplink and downlink.

The invention eliminates the influence of the radio wave transmission on the timing accuracy of the conversion point by calculating the radio wave transmission time delay between the base station and the repeater. The positions of the two switching points acquired by this method are not affected by interference from user terminals or adjacent base stations.

Description of drawings

Fig. 1 is the physical channel signal format of TD-SCDMA;

FIG. 2 is a structural diagram of a system for realizing precise control of uplink and downlink switching by the repeater provided by the present invention.

Detailed ways

In order to make the solution of the present invention clearer, the present invention will be further described in detail below in conjunction with examples.

The present invention provides a system for precisely controlling uplink and downlink switching by a repeater, as shown in Figure 2, which includes: a control center, a communication link and a repeater, and a calculation and control module and a satellite positioning receiver are arranged in the repeater , repeater radio frequency link, the control center transmits the base station location information and the time information of the two conversion points to the repeater through the communication link; the satellite positioning receiver transmits the obtained repeater location information and standard time to the computer and the control module; the calculation and control module calculates the radio wave transmission time delay and the positions of the two switching points of the repeater, and controls the radio frequency link of the repeater to switch up and down.

Use the following steps to realize the uplink and downlink switching control of the repeater:

Step 1. The control center obtains the location information of the base station and the time information of the two switching points from the wireless network controller. The base station location information refers to the latitude and longitude of the base station. The time information of the two transition points includes the start time of a certain system frame and the position of the second transition point, and may also be the start time of a radio frame and subframe and the position of the second transition point. For example, the parameter t is used to represent the GMT at the start time of a certain system frame, and the parameter n is used to represent that the second transition point is located between the nth time slot and the n+1th time slot of each subframe.

Step 2: The control center transmits the location information of the base station and the time information of the two conversion points to the calculation and control module through the communication link. The communication link between the control center and the calculation and control module can be established by using short messages.

Step 3: The calculation and control module uses the satellite positioning receiver to obtain the position information and standard time of the repeater. The satellite positioning receiver can be a GPS receiver or other types of satellite receivers.

Step 4, the calculation and control module calculates the radio wave transmission time delay between the base station and the repeater according to the position information of the base station and the repeater.

Step 5. The calculation and control module calculates the precise repeater switching point time according to the radio wave transmission delay between the base station and the repeater and the time information of the two switching points, and generates a control signal to control the RF chain of the repeater switch between uplink and downlink.

When the position of the base station or the time information of the two conversion points are adjusted, steps 1 to 5 are repeated.

Claims (3)

1, a kind of method that time division synchronous code division multiple access system repeater realizes uplink and downlink switching, it is characterized in that, this method comprises the steps: a. The control center obtains the location information of the base station and the time information of two switching points from the wireless network controller or the base station; b. The control center uses the communication link to transmit the base station location information and the time information of the two conversion points to the calculation and control module; c. The calculation and control module uses the satellite positioning receiver to obtain the position information and standard time of the repeater; d. The calculation and control module calculates the radio wave transmission delay between the base station and the repeater according to the position information of the base station and the repeater; e. The calculation and control module calculates the precise time of the repeater conversion point according to the radio wave transmission delay between the base station and the repeater and the time information of the two conversion points, and generates a control signal to control the radio frequency link of the repeater Perform uplink and downlink switching. 2. Realize the repeater control uplink and downlink switching system, including: control center, communication link and repeater, the repeater is equipped with calculation and control module, satellite positioning receiver, repeater radio frequency link, which is characterized in that : The control center transmits the position information of the base station and the time information of two conversion points to the repeater through the communication link; the satellite positioning receiver transmits the acquired position information and standard time of the repeater to the calculation and control module; the calculation and control The module calculates the radio wave transmission time delay and the positions of the two switching points of the repeater, and controls the radio frequency link of the repeater to switch up and down. 3. The method according to claim 1, characterized in that the location information of the base station and the time information of the two transition points transmitted through the communication link are dynamically updated.

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