KR19990061218A - Grouping and Ungrouping Using Power Control in Microcell Environments - Google Patents

Abstract

The present invention relates to a method of reducing a signal load on a base station and a better quality service to a subscriber by lowering a handoff signal between cells through grouping and ungrouping each cell by power control in a micro cell environment. A first step of gradually increasing the power of the center cell so that a terminal at a boundary between the center cell and a neighboring cell is handed over to the center cell; Power continues to increase until the center cell covers the rest of the cell, and the neighboring cells gradually lower the power, keeping the cell radius small so that the terminal at the boundary between the center cell and the neighboring cell is handed over to the center cell. Second step; And a third step of increasing the power of the center cell to cover the neighboring cell, and gradually decreasing the power of the neighboring cell to turn off the power when the center cell covers the whole. The method includes: gradually decreasing power of a center cell and gradually increasing power by turning on a power of a neighboring cell so that a terminal at a boundary between the center cell and the neighboring cell is handed over to the center cell; Gradually decreasing the power of the center cell until the power of the original state is increased, and increasing the power of the neighboring cell until the power of the original cell, so that the terminal at the boundary between the center cell and the neighboring cell is handed over to the center cell; And maintaining the power in the state prior to the grouping of the center cell and the neighboring cells.

Description

Grouping and Ungrouping Using Power Control in Microcell Environments

The present invention relates to a technique for better service to subscribers in a micro cell environment and a technology for reducing signal load on a base station. In particular, in a micro cell environment, a plurality of cells are grouped together as a single micro cell by power control. When a large number of subscribers occur, the present invention relates to a method of ungrouping an existing state and operating the original small cell again.

In a conventional code division multiple access (CDMA) cellular system, 12 base station controllers are connected to one switching station, and 16 or 48 base station transceiver systems (BTSs) are connected to each base station controller. To form.

The switching center and base station control unit, and the base station control unit and the BTS are located in the same office, and the BTS is installed in the area where the desired subscriber is located. In addition, the home location register covers a large number of exchanges in terms of location registration, subscriber information management, call processing and supplementary services, access to authentication centers, and support for short message service (SMS).

In this structure, the subscriber's signal is transmitted to the base station controller by receiving the signal transmitted by the high frequency signal on the air in the BTS, and then modulating the digital signal to the base station controller, and the base station controller vocodes the signal. When it is delivered to the exchange, it is delivered to the desired subscriber. In this case, if the signal goes to the wired subscriber, it is transmitted to the desired subscriber through the public through the Public Switched Telephone Network (PSTN) network through the switching center.

Each BTS covers one cell or sector, which does not change fluidly when the subscriber's capacity (14 channels for 13k vocoder, 20 channels for 8k vocoder) is determined. Therefore, when a large number of subscribers are suddenly exited, a lot of efficiency is lost, and a call is disconnected due to the load of the task of continuing handover when the fast subscriber moves.

In addition, there is a difficulty in installing equipment suitable for an urban high frequency environment, and there is also a difficulty in increasing a required capacity due to an increase in many subscribers. Thus, the cell becomes smaller and smaller to increase the capacity, thereby increasing unnecessary handoffs and lowering the performance of the call.

According to the internal structure of the current base station, a base station having a sector cell structure has antennas for each sector, so that the PN (Pseudo Noise) offset and the long code to use the signals transmitted from the switching center to the base station controller → BTS for each sector. The Walsh code of each channel is multiplied by the modulator chip and transmitted.

Looking at the channel card, there are two modulator chips. There are eight channels in the modulator, and there are 16 channels in one channel card. Three paths to each of the three sectors on each channel are provided to sum the outputs of each channel.

In this structure, when a terminal moves between sectors, a handover occurs and a call is disconnected.

Therefore, in order to solve the problems as described above, the number of cells is increased and the number of calls is increased at the time of increasing the power of one reference cell by handoff the subscriber of the other cells to the reference cell to absorb and group In this case, the purpose of the present invention is to ungroup again by lowering the power of the reference cell and increasing the power of the other cells at the time when the number of calls increases again.

1 is an overall configuration diagram in a macro environment

2 is an overall configuration diagram of a micro cell system;

3 shows the initial cell structure before grouping begins

4 is the initial stage of grouping

5 is the medium stage of grouping

6 is the late stage of grouping

7 shows the initial cell structure before starting ungrouping

8 is an initial stage of ungrouping

9 is the medium stage of ungrouping

10 is the final stage of ungrouping

One preferred embodiment for grouping of the present invention for achieving grouping and ungrouping by using power control in a microcell environment according to the present invention is to increase the power of the center cell to the boundary line between the center cell and the neighboring cell. A first step of allowing a terminal to be handed over to a center cell;

Power continues to increase until the center cell covers the rest of the cell, and the neighboring cells gradually lower the power, keeping the cell radius small so that the terminal at the boundary between the center cell and the neighboring cell is handed over to the center cell. Second step; And

The central cell increases with enough power to cover the surrounding cells, and the peripheral cells comprise a third step of turning down the power when the central cell covers the whole, gradually lowering the power.

In the present invention, it is preferable to perform grouping when there are few users.

One preferred embodiment of the ungrouping method of the present invention for achieving the above object,

CLAIMS 1. A grouping cell, comprising: a first step of gradually reducing power of a center cell and gradually increasing power by turning on power of a neighboring cell, so that a terminal at the boundary between the center cell and the neighboring cell is handed over to the center cell;

A second step of gradually decreasing the power of the center cell until the power of the original state and increasing the power of the neighboring cell until the power of the original cell so that the terminal at the boundary between the center cell and the neighboring cell is handed over to the center cell; And

And a third step of maintaining the power of the center cell and the neighboring cells prior to grouping.

In the present invention, it is preferable to perform ungrouping when there are many users.

Referring to FIG. 2, a micro cell system in which grouping and ungrouping will be used will be described. The present micro system separates a base station installed in a PCS from a digital hardware portion and a high frequency transceiver portion, and uses a subcarrier multiplexing (SCM) technique between them. The connection was made using the optical fiber based on the base. In other words, the structure is divided into micro base station transformers (mBSCs), which manage the resources centrally and serve the digital hardware portion of the existing base station that can support multiple micro cells, and connects the Isoi with an optical cable. It is structured.

mBSC centrally manages small base stations and dynamically allocates channels to each cell to economically expand system capacity as traffic increases, enabling cell design to meet optimal conditions.

Instead of separately installing a GPS (Global Position System) receiver in these small base stations, the reference clock signal output from the GPS receiver of the mBSC is transmitted through the HFR network to maintain synchronization between each small base station. This reduces mBSC price, reduces weight and size, and enables flexible cell design in shaded areas of tunnels and indoors where GPS antenna installation is difficult. Systems and networks having such functions can be easily interworked with other communication networks and can flexibly respond to various wireless communication services.

In such a system, a plurality of cells can be dynamically grouped and ungrouped so that an optimal cell coverage and capacity can be harmonized according to the fluid traffic.

Referring to FIG. 3, FIG. 4, FIG. 5, and FIG. 6, a process of grouping eight cells into one cell will be described.

When the number of cells increases and decreases, the power of the center cell is gradually increased as shown in FIG. 4 at the initial eight cell states of FIG. 3. Due to an increase in the power of the center cell, a terminal located at the boundary between the reference cell and the neighboring cell is handed over to the reference cell.

As shown in FIG. 5, the power is continuously increased until the remaining cells are covered. At this time, the remaining cells relatively lower the power intensity to keep the cell radius small. In this case as well, the terminal in the boundary between the reference cell and the side cell is handed over to the reference cell.

As shown in FIG. 6, the power is increased to cover eight cells. On the contrary, the remaining cells gradually decrease the power, and when the reference cell covers the entire power, the power is turned off, and the eight cells operate as if they were grouped into one reference cell. It is done.

In addition, the process of ungrouping into eight cells will be described with reference to FIGS. 7, 8, 9 and 10.

In the grouped state as shown in FIG. 7, the power of the reference cell is gradually reduced as shown in FIG. 8, and the remaining cells turn on to increase the power. Due to an increase in the power of the reference cell, the terminal located at the boundary between the reference cell and the side cell is handed over to the reference cell.

As shown in FIG. 9, the reference cell continuously decreases gradually to the original power, while the size of the remaining cells gradually increases to the original power. At this time, the terminal in the boundary between the reference cell and the neighboring cell is handed over to the reference cell.

As shown in FIG. 10, the reference cell and the remaining cells are ungrouped before being grouped by maintaining the power of the original state.

According to the present invention operating as described above, when capacity is required, the number of users is reduced, but when the number of users is small, the group is operated as one cell to suppress handover occurrence, thereby increasing the success rate of the call and the load of the base station. When the capacity is reduced and the capacity is needed, the grouped cells are ungrouped and operated in the previous state, so that the cells can be rearranged in various ways according to the traffic demand of the user.

Claims (4)

A first step of gradually increasing the power of the center cell so that a terminal at the boundary between the center cell and the neighboring cell is handed over to the center cell; Power continues to increase until the center cell covers the rest of the cell, and the neighboring cells gradually lower the power, keeping the cell radius small so that the terminal at the boundary between the center cell and the neighboring cell is handed over to the center cell. Second step; And Using a power control in a microcell environment, comprising a third step of increasing the power of the center cell to cover the surrounding cell, and gradually turning the power down to turn off the power when the center cell covers the whole. Grouping method. 4. The method of claim 1, wherein grouping is performed when there are few users. CLAIMS 1. A grouping cell, comprising: a first step of gradually reducing power of a center cell and gradually increasing power by turning on power of a neighboring cell, so that a terminal at the boundary between the center cell and the neighboring cell is handed over to the center cell; A second step of gradually decreasing the power of the center cell until the power of the original state and increasing the power of the neighboring cell until the power of the original cell so that the terminal at the boundary between the center cell and the neighboring cell is handed over to the center cell; And And a third step of maintaining the power of the center cell and the neighboring cells prior to grouping. 4. The method of claim 3, wherein ungrouping is performed when there are many users.