KR20000031130A - Method for minimizing overlapping area between base stations in two-way paging system - Google Patents

Abstract

PURPOSE: A method for minimizing overlapping area between base stations in two-way paging system is provided to control the transmit power of an RF signal transmitted to a pager, thereby minimize the overlapping area decreasing the service area of a base station. CONSTITUTION: A method for minimizing overlapping area between base stations in two -way paging system comprises steps of: receiving a radio frequency signal; measuring the receive power level of the received radio frequency signal; storing the measured receive power level with an ID of the pager in a receive power table; deciding a transmit power lever in reference to the receive power lever; and transmitting an RF signal having the decided transmit power level to the pager.

Description

Minimization of overlapping area between base stations in bidirectional paging system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-way paging system. In particular, when a message is transmitted / received using a Capture Division Packet Access (CDPA) protocol, it occurs in an overlapping area. The present invention relates to a method for minimizing overlapping areas between base stations in a bidirectional paging system for minimizing interference between base stations.

A paging system is a system that provides various pager services wirelessly to a pager. The paging system has a base station for each cell, which is an allocated area, and the base station calls page data. Is received from the paging terminal and transmits a radio call signal to the pager of the corresponding area.

The base station of the paging system receives the call data generated based on the information received from the subscriber from the switching center, combines the call data according to the protocol being used in the system, and uses GPS (Global Positioning) to simultaneously transmit the call data (Simulcast). System) In synchronization with absolute time information (reference clock signal) received from a receiver, the combined call data is loaded on a radio frequency (RF) signal and broadcasted to a corresponding pager.

The advanced bidirectional paging system can transmit and receive messages between the pager and the base station according to the CDPA protocol. In the case of the bidirectional paging system using the CDPA, a plurality of base stations transmit only necessary data to each other.

1 is a diagram illustrating a configuration of a base station of a bidirectional paging system according to the prior art, comprising: a system communication unit 110 for transmitting and receiving a control signal and a message with an exchange station; A message controller 120 for packetizing a message received from the system communication unit, analyzing the message packet, and delivering the message packet to the system communication unit; A power control unit 130 for determining a power level of the radio frequency signal transmitted to the pager using the control signal received from the system communication unit; And a radio frequency unit 140 for transmitting a radio frequency signal including a message provided from the message control unit, a radio frequency signal having a power level determined by the control of the power control unit, and receiving a radio frequency signal from the pager.

In the bidirectional paging system configured as described above, signals from two base stations may collide in an area that receives radio frequency signals from two or more base stations. That is, in the overlapping region where signals from two or more base stations overlap, since the transmit power levels of the base stations are fixed, when the base stations transmit different message packets, the pager receives the damaged message packet due to the collision. This happens.

In the prior art, when a pager receives a corrupted packet, the pager attempts to re-receive. However, since packets transmitted from the multiple base stations to the overlapped areas continue to collide, there is a problem that the pagers cannot receive normal packets unless the pagers in the overlapped areas move to other areas.

Accordingly, an object of the present invention, which was devised to solve the problems of the prior art operating as described above, is a radio frequency signal transmitted by a base station generating an overlapping area to the pager according to the reception level of the radio frequency signal sent by the pager. It is to provide a method of minimizing overlapping areas between base stations in a bidirectional paging system that reduces the service area of the base station by controlling the transmission power of the base station.

Other objects and advantages of the present invention will become more apparent from the following detailed description of the invention and the accompanying drawings.

1 is a diagram illustrating a configuration of a base station of a bidirectional paging system according to the prior art.

2 is a diagram illustrating a configuration of a base station of a bidirectional paging system to which the present invention is applied.

Figure 3 is a flow chart showing an embodiment of the overlapping area minimization method according to the present invention.

4 is a diagram of a transmit power level determined by the present invention.

5 is an embodiment of a method for minimizing overlapping areas according to the present invention.

<Explanation of symbols for main parts of the drawings>

110,210: system communication unit 120,220: message control unit

130,230: power control unit 140,240: radio frequency unit

A preferred embodiment of the method for minimizing overlapping areas between base stations in the bidirectional paging system according to the present invention, which is designed to achieve the above object,

Receiving, by the base station of the bidirectional paging system, the radio frequency signal from the pager;

Measuring a received power level of a received radio frequency signal;

Storing the measured received power level together with the ID of the pager in a received power table;

Determining a transmit power level with reference to the received power level; And

And transmitting the radio frequency signal having the determined transmit power level to the pager.

Another preferred embodiment of the method for minimizing overlapping area between base stations in the bidirectional paging system according to the present invention,

Transmitting, by the base station of the bidirectional paging system, to a pager, a radio frequency signal having a maximum transmit power level of the base station;

Receiving a response radio frequency signal from the pager;

Measuring a received power level of the response radio frequency signal;

Storing the measured received power level together with the ID of the pager in a received power table;

Determining a transmit power level with reference to the received power level; And

And transmitting the radio frequency signal having the determined transmit power level to the pager.

Another preferred embodiment of the method for minimizing overlapping area between base stations in the bidirectional paging system according to the present invention,

Generating an overlapping region between the first base station and the second base station;

The first base station removing the overlap area by reducing the transmit power level.

In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

The present invention relates to a method for preventing a collision of a call in an overlapping area where a plurality of base stations are affected. The present invention provides a method for transmitting radio frequency signals to a pager according to a reception level of a radio frequency signal received from a pager. Determine the power level. In the CDPA bidirectional paging system, the base station transmits only one message packet to one pager at a time. Therefore, the base station estimates the distance to the pager from the power level of the radio frequency signal received from the pager in communication with itself, and determines the power level of the radio frequency signal to be transmitted to the pager.

If a pager is located in an overlapping area, one base station reduces its service area, thereby removing or reducing the overlapping area in an instant. The surrounding base stations are then less affected by the base stations. That is, when a pager communicates with one base station in an overlapping area of a plurality of base stations, the overlapping area is instantaneously reduced by reducing the transmission power level of radio frequency signals transmitted to the pager by neighboring base stations that do not communicate with the pager. Remove

FIG. 2 is a diagram illustrating a base station configuration of a bidirectional paging system to which the present invention is applied. As illustrated, a system communication unit 210 for transmitting and receiving a control signal and a message to and from an exchange station; A message control unit 220 for packetizing a message received from the system communication unit, analyzing the message packet, delivering the message packet to the system communication unit, and determining a transmission power level from a received power table of a previously stored pager; A power control unit 230 for determining a power level of the radio frequency signal transmitted to the pager using the control signal received from the system communication unit and the transmission power level received from the message control unit; And a radio frequency unit 240 for transmitting a radio frequency signal including a message provided from the message control unit, a radio frequency signal having a power level determined by the control of the power control unit, and receiving a radio frequency signal from the pager.

The message controller 220 reads a received power level of a pager to which a current signal is to be transmitted from a received power table storing a received signal strength indicator (RSSI) received for each pager, and transmits a radio frequency to the pager. Determine the power level of the signal.

Since the base station of the bidirectional paging system transmits only one message packet at a time to the radio frequency signal to the pager, the transmitted packet only needs to receive exactly the pager desired by the base station. Therefore, the present invention adjusts the transmission power level of the base station for each message transmitted according to the power level of the signal received by the corresponding pager.

Hereinafter, the operation and effects of the present invention will be described in detail with reference to the accompanying drawings.

3 is a flowchart illustrating an embodiment of a method for minimizing overlapping areas according to the present invention. If the pager sends a radio frequency signal having a predetermined power level to the base station to send a message packet, in step S110, the base station receives the radio frequency signal from the pager, and in step S120, the reception power level of the received radio frequency signal. Measure

In step S130, the base station stores the measured reception power level together with the ID of the corresponding pager in the reception power table. The form of the reception power table is shown in Table 1.

Received Power Table Pager ID Receive power level 0 XXX One XXX ... ...

When the base station intends to transmit a message packet to a pager whose reception power level is recorded in the reception power table, in step S140, the base station refers to the reception power level of the corresponding pager read from the reception power table and transmits the radio frequency to the pager. Determine the transmit power level of the signal. 4 shows a diagram of the transmission power level determined by the present invention. When the reception power level is very small, the transmission power level of the base station is maximum, and when the reception power level is high, the transmission power level is minimum. In step S150, the base station transmits a radio frequency signal having the transmission power level determined in step S130 to the pager.

However, when the base station needs to send a message packet to a pager whose ID is not stored in the reception power table, the base station first sends a radio frequency signal to the corresponding pager using the maximum power level. When the pager receives the radio frequency signal and transmits a radio frequency signal including a response message thereto, the base station measures the received power level of the received radio frequency signal in response to generate a receive power table, and then transmits the transmit power level. Use it as a basis for decision.

Figure 5 shows an embodiment of the overlapping area minimization method according to the present invention. Before adjusting the power level of the base station, the first base station 10 has a first service area 1 and the second base station has a second service area. Therefore, since the first pager 11 and the second pager 12 located in the overlapped area receive signals from both the first base station and the second base station, a collision of message packets occurs.

Then, the second base station 20 reduces the transmission power level by using the radio frequency signal received from the second pager 12, thereby reducing the second service area to the third service area 3. The first pager then receives only signals from the first base station and the second pager only receives signals from the second base station, allowing both pages to receive undamaged message packets.

In the case of FIG. 5, if the ratio of overlapping areas among the total service areas of the two base stations is 1/2, when at least one pager is located in the overlapping area and the two base stations transmit message packets, the probability of collision between packets is maximum. 3/4. However, if the service area of one base station is reduced, the probability of collision between packets is reduced to 1/4.

The present invention can be variously modified and can take various forms and only the specific embodiments thereof are described in the detailed description of the invention. It is to be understood, however, that the present invention is not limited to the specific forms mentioned in the detailed description of the invention, but rather includes all modifications, equivalents, and substitutions within the spirit and scope of the invention as defined by the appended claims. It should be understood to do.

In the present invention operating as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

The present invention reduces the transmission power level of a specific base station in an overlapping area between base stations where a collision of message packets occurs, thereby suppressing the collision of packets transmitted from the base stations with each other, thereby improving the quality of the message packet provided to the pager. It is effective in increasing and providing quality communication service to the pager.

Claims (8)

Receiving, by the base station of the bidirectional paging system, the radio frequency signal from the pager; Measuring a received power level of a received radio frequency signal; Determining a transmission power level with reference to the measured reception power level; And Transmitting a radio frequency signal having a determined transmission power level to a pager. The method of claim 1, wherein measuring the received power level comprises: And storing the measured received power level together with the ID of the pager in a received power table. The method of claim 1, wherein determining the transmission power level, And determining a transmit power level to be inversely proportional to the received power level. The method of claim 1, wherein determining the transmission power level, A method for minimizing overlapping areas between base stations in a bidirectional paging system, wherein the received power level corresponding to a pager to which a radio frequency signal is to be transmitted is searched from the received power table and the transmit power level is determined by referring to the found received power level. Transmitting, by the base station of the bidirectional paging system, to a pager, a radio frequency signal having a maximum transmit power level of the base station; Receiving a response radio frequency signal from the pager; Measuring a received power level of the response radio frequency signal; Determining a transmission power level with reference to the measured reception power level; And Transmitting a radio frequency signal having a determined transmission power level to a pager. The method of claim 5, wherein measuring the received power level, And storing the measured received power level together with the ID of the pager in a received power table. The method of claim 5, wherein the determining of the transmission power level, And determining a transmit power level to be inversely proportional to the received power level. Generating an overlapping region between the first base station and the second base station; And removing the overlapping area by reducing the transmission power level by the first base station.