FI112907B - Handling of a cell layer - Google Patents

Description

1,112,907 f

CELL LAYER TREATMENT

The invention relates to telecommunication systems. In particular, the invention relates to a method of computationally optimizing capacity utilization in a mobile communication network divided into cells and cell layers. In the method, the terminals are placed in cells and cell layers of the mobile network, after which the level of service of the terminals is determined. If the terminal does not receive the service, an attempt is made to place the terminal 10 in a new cell layer. The countdown is terminated when all terminals receive the service or when it is found that it is not possible to serve all terminals with a limited number of cell layer transfers.

15

BACKGROUND OF THE INVENTION

Due to the popularity of mobile systems, the number of mobile devices has increased significantly. With this, the importance of designing mobile systems, in other words radio 20 networks, has become more prominent.

Telecommunication systems have been developed to send information signals from a source to a physically remote user. Both analog and digital methods have been used to transmit such information signals over communication channels that connect the source and the user. Digital methods have several advantages over analogue technologies, including, for example, better immunity to channel noise and interference, better capacity 30, and traffic security encryption.

,, When transmitting an information signal from a source • on a communication channel, the information signal is first converted to a suitable format for efficient transmission on the channel. The transformation or modulation of an infomation signal; 35 Lille includes changing carrier parameters based on an information signal such that the spectrum of the resulting Mor 2 112907 dulated carrier is suitable for the channel bandwidth. At the user point, the original message signal is repeated based on the modulated carrier as the carrier propagates on the channel. Such repetition is generally obtained by the inverse of the modulation process used by the source transmitter.

In addition, modulation enables multiple access, i.e. multiple signals being transmitted simultaneously on the same channel. Multiple access communication systems 10 often include a number of remote users who need an immediate service rather than a continuous communication channel allocation. The communication systems designed for short periods of time are designated as multi-access communication systems.

A particular type of multiple-access catechol system is a spread spectrum system. In a spread spectrum system, the modulation technique used leads to a wide spread spreading of the transmitted signal over a communication channel. One type of multiple access spread spectrum is a code division multiple access modulation (CDMA) system. Other multi-access communication technologies, such as time division multiple access (TDMA), are also known. and Frequency Division Multiple Access (FDMA).

; However, CDMA has several significant advantages; and compared to these modulation techniques. The basics of CDMA technology are described in EN 301 055 "Transmission and Multiplexing; Digital Radio Relay Systems; Direct Sequence Code Division Multiple Ac-30 cess; Point-to-multipoint DRRS in frequency bands in the range 1 GHz to 3 GHz". In a CDMA cellular telephone system, the same frequency channel is used for all cellular communications.

In the near future, the so-called third; 35 generation mobile communication systems are becoming more common; terrestrial. An example of this is planned; Global System for Mobile Communications (UMTS, »112907 3

Universal Mobile Telecommunications System), which implements broadband packet-based multimedia data transmission. Multimedia often consists of text, audio, photos and moving images. Since the land-to-5 air mobile system transmits information in a packet-based format, it is easy to connect to the Internet. The global mobile system also accelerates data transfer from the current 9.6 Kbit / s to up to 2 Mbit / s, enabling completely new applications for mobile terminals.

The optimization of capacity in the mobile communication network becomes particularly problematic. Frequently mobile terminals move rapidly from one cell to another. In a code division multiple access modulation system, a mobile communication network may be constructed in layers, for example, one layer may be ubiquitous throughout, and other layers may increase capacity or provide a particular service in certain areas. Usually, each cell layer has its own carrier. In examining whether a given service is provided or sufficient in a particular area,; then you need to evaluate which cell layer you want to place the terminals on. It would be advantageous if the terminals; 25 teas are located primarily in the strongest and most frequent. to serve the nearest cell. This will reduce system interference. If the terminals are placed on different cell layers regardless of the service, the system 's capacity can be optimized.

30 A prior art solution in which a cellular | The sizes are scaled to obtain the optimum; ; transmit power and cell size. The solution optimizes · (transmission power, but does not solve the problem of providing an optimal »*» / service level for mobile stations in the cellular area.

The object of the present invention is; eliminate or reduce the above problems. It is an object of the invention to provide a remarkably efficient method for designing an optimum mobile communication network so that the mobile network terminals are served at the lowest possible cost.

5

SUMMARY OF THE INVENTION

By means of the invention, the service level of the terminals in the mobile communication system is computationally optimized by placing the terminals in the cells and cell layers of the mobile communication network. The computation is continued until all the terminals have a service or until it is detected that transferring the terminal to a different cell layer cannot provide service to the terminal.

The invention relates to a method in which the capacity of a mobile communication network is optimized. The mobile communication network is divided into cells and cell layers. In the method, the terminals of the mobile network are placed in cells. The method first places the terminals 20 in one or more cell layers, then determines the field strength values for each cell and checks whether said terminals are serving based on the current cell layer arrangement. If, based on the scan, the terminal does not receive 25 services, the terminal is transferred to another cell layer; which second cell layer is determined based on the field strengths assigned to the cells of the cell layers. If all terminals receive the service based on the scan, the scan will stop. On the other hand, the scan is also terminated even if the terminal is not receiving service and if the terminal cannot be transferred to another cell layer.

:; Before scanning, the terminal can be configured •. geographic locations for you and your cells. Prior to 35 checks, a stop condition is often specified, which is how many cell layers are allowed to move. The Export. ; Before scanning, it is often determined which cell layer each cell is. The terminal is primarily located on the cell layer where the cell strength having the highest field strength is the highest. On the other hand, the terminal is first placed on the cell layer where it is desired to provide the terminal with the desired service. Further, the terminal is primarily located in the cell layer where the cell strength of the cell having the highest field strength is greatest if the plurality of cell layers provide the service desired by the terminal.

It is determined for each terminal whether they receive service from that cell layer. The terminal is primarily located in the cell layer where the cell with the highest field strength has the highest field strength, if the terminal does not receive service due to the check. Further, the terminal is primarily located on the cell layer where it is desired to primarily provide the terminal with the desired service if said terminal does not receive the service due to the check. The terminal is preferably located on the cell layer where-; the field strength of the cell with the highest field strength is the greatest if multiple cell layers; 25 provide the service desired by the terminal and if the master does not receive the service based on the check. The terminal does not receive the service if the terminal has been transferred sufficiently many times from one cell layer to another and has not received the service. The terminal does not receive service if the 30 terminals cannot be transferred to another cell layer.

: Checking whether the terminal will receive the service again if; the terminal is transferred to the second cell layer.

In a preferred embodiment of the invention, a mobile communication network is designed having a plurality of mobile stations and telephones within its 35 area; base stations. Given the location of the mobile stations and the services they require, the invention can be used to determine optimal radio field strengths for base stations.

The advantages of the invention over the prior art are that it is possible to optimize the capacity of the mobile communication network. The invention is able to calculate the optimum mode of operation of a mobile communication network, whereby the terminals located in the cell layers are served as efficiently as possible. In particular, interference in the mobile communication system is reduced because each cell-10 layer operates on its own radio frequency. Terminals can also be served more efficiently because it is possible to use multiple radio frequencies to implement the services of the mobile communication system. Thus, cost savings are achieved through more efficient operation of the system 15 and the range of services offered in the mobile network is diversified, whereby even video conferencing to a mobile terminal can be provided.

2 0 LIST OF PHOTOS

The invention will now be described, by way of example, with reference to the accompanying drawings, in which Figure 1 is a description of a system according to the invention; Figure 2 is a flow chart of a method according to the invention; and Figure 3 illustrates an embodiment of the invention.

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DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a system according to the invention. The mobile communication system consists of cells C1, C2, C3, C4 and C5. Each cell has a base station 35 BS1, BS2, BS3, BS4 and BS5 and often at least one terminal MS1, MS2, MS3, MS4 and MS5. The terminal is typically a mobile station, such as Nokia 3120. Cell layers are further assembled from cells. The cell layer consists of base stations having the same transmission frequency. For example, cells C1 and C2 form a cell layer 5, CL1, which provides certain services to mobile terminals MS1 and MS2 moving in the cellular area.

Figure 2 shows a method diagram of the invention. Before starting the counting, the variables needed during the count are determined, such as the geographical location to be assigned to each user and cell, the field strength value to be calculated for each cell, the allowed number of cell layovers, and the cell layer variable to determine the cell layer to which. When the count is started, the terminals are placed in the cell layers, step 21. The terminal is primarily located in the cell layer with the highest field strength of the cell with the highest field strength and which primarily provides the user with the required 20 land service. Next, a service value is calculated for each terminal, step 22. The service value indicates whether the terminal receives service in the current cell layer; velua. If a terminal does not receive the service, then it is checked whether the terminal can be transferred to another cell: 25, steps 23 and 24. If the terminal can; move, so the terminal is moved, step 25. The terminal is prioritized, i.e. the terminal is to be located on the cell layer where the cell field having the highest field strength has the highest cell strength and primarily provides the service required by the user. If the terminal has been 'moved' a sufficient number of times, or if the terminal cannot be moved to another cell layer, then the terminal will not receive service, after which the counting will be terminated. Once the terminal transfer has been completed, the service value for the transferred terminal devices is recalculated. If all terminals are served, the counting, step 26, is terminated.

Figure 3 shows an embodiment of the invention. The mobile communication system consists of terminals MS1, MS2, MS3, MS4, MS5 and base stations BS1, BS2, BS3, BS4, BS5, BS6 and BS7. That is, a radio field is formed around each base station, i.e., cells C1, C2, C3, C4, C5, C6 and C7. The first three base stations use the same transmission frequency, so they form one wide cell layer CL1. Other base stations use a unique transmission frequency, so they form a cell layer the size of their own cell area. The first terminal MSI communicates with the base station BS1. Further, the second terminal MS2 is located in the area of three cell layers, so the terminal MS2 can select any cell layer. Typically, as illustrated by the invention, the terminal MS2 prioritizes the cell layers according to the radio frequency and selects the cell layer of the strongest radio field. On the other hand, the terminal MS2 also looks at the services provided by the cell layer, and if the strongest cell layer does not provide the required services, the terminal MS2 selects the next cell layer; layer. In the example case, the terminal I 25 selects the base station BS6.

; Frequently, base stations are located either in the shadows of the radio field or in the terminals of the terminals. Cell layers can provide different services. For example, the first cell layer CL1 provides basic telephone services, while the second C6 and third cell layer C7 may provide more bandwidth-intensive multimedia services such as video conferencing.

The invention defines the required services and geographical locations of the terminals, which are used to locate the terminals suitably in the cell layers. This ensures service for as many terminals as possible. In one embodiment of the invention 112907 9, all three cell layers provide telephone service to terminals. In this case, the three base stations can serve the terminal cluster better than usual.

The invention is not limited solely to the above exemplary embodiments, but many modifications are possible within the scope of the inventive idea defined by the claims.

Claims (14)

1. Method for optimizing the use of; Capacity in a mobile network, which is divided into cells (Cl-CN) and cell layers (CL1-CLN), wherein method terminal equipment (MSI-MSN) in the mobile network is placed in the cells, characterized in that the method comprises the following: step: placing said terminal equipment into one or more of said cell layers; determining field strength values for each cell; Checking whether said terminal equipment receives service on the basis of placement in the cell layer for the moment; moving the terminal equipment to another cell bearing, if said terminal equipment on the base of the control is not serviced, which other cell bearing is determined on the basis of field strengths determined for the cell layer's cells; and terminating the control if all terminal equipment is serviced at the base of the control, or if said terminal equipment is not serviced and if said terminal equipment cannot be moved to another mentioned cell store. 2. A method according to claim 1, wherein the control is determined for said terminal equipment and said geographical location before said control. The method of claim 1 or 2; characterized in that, prior to the control; is terminated a termination condition which includes, how; 25 multiple movements of cell layers were allowed. A method according to claim 1, 2 or 3, characterized in that before the control it is determined on which cell layer each cell is on. 5. A method according to claim 1, 2, 3 or 30, characterized in that said terminal equipment is placed primarily in the said cell: layer of said cell having the greatest field strength, field strength is the greatest. 6. A method according to claims 1, 2, 3, 4 or 5, characterized in that said terminal equipment is placed primarily in the said cell layer where it is primarily intended to offer said terminal equipment the service it wishes. A method according to claims 1, 2, 3, 4, 5 or 6, characterized in that said terminal equipment is placed primarily to said cell layer of said cell having the greatest field strength, field strength is greatest, if several of said cell bearings offer the service that said terminal equipment desires. 10 8. A method according to claims 1, 2, 3, 4, 5, 6 or 7, characterized in that for each said terminal equipment it is determined if they receive service of said cell bearing. Method according to claims 1, 2, 3, 4, 5, 6, 7 or 8, characterized in that said terminal equipment is placed primarily in the said cell layer of said cell having the greatest field strength, greatest, if said terminal equipment is not serviced at the base of the control. A method according to claims 1, 2, 3, 4, 5, 6, 7, 8 or 9, characterized in that; said terminal equipment is placed primarily in the said cell store where it is primarily desired to offer said terminal equipment the service it desires. can, if said terminal equipment is not serviceable. on the base of the control. Method according to claims 1, 2, 3, 4, 5,6,7,8,9 or 10, characterized in that said terminal equipment is placed primarily in said cell layer being said cell of said cell; has the greatest field strength, field strength is greatest, if several of said cell bearings offer the service that said terminal equipment desires and if said terminal equipment fails to operate on the basis of control. 112907 Method according to claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11, characterized in that said terminal equipment is not serviced if said terminal equipment has been moved sufficiently many times from said cell bearing to another and it does not have greasy operation. A method according to claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, characterized in that said terminal equipment cannot be serviced if said terminal equipment cannot be moved to another mentioned cell bearing. Method according to claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13, characterized in that it is checked if said terminal equipment receives service again, if said terminal equipment has been moved to another mentioned cell store. in