RU2126591C1 - Mobile cellular communication system - Google Patents

Abstract

FIELD: mobile radiotelephone communications. SUBSTANCE: system is provided with regional communication controllers inserted between mobile system switching center and base stations; it is also provided with interface for direct connection to common-user telephone network. EFFECT: provision for communication with remote regions of service territory. 1 dwg

Description

 The invention relates to mobile radiotelephone communications and can be used in the organization of cellular mobile networks.

 A well-known system of cellular mobile communications GSM (Gromakov Y. A. Standards and systems for mobile radio communications, electronic communications technology. T. 67.-M .: 1996, pp. 87-106).

 The main elements of the GSM system are a switching subsystem containing a mobile switching center, a base station system including base station controllers, base station transceivers and mobile subscriber stations.

 The mobile switching center provides control of the mobile communication system, all types of connections for mobile stations of subscribers and an interface with the public switched telephone network.

 Base station controllers are connected to the mobile switching center via the A-interface and provide control of a group of base station transceivers.

 Base station transceivers are connected to base station controllers via the Abis interface and provide radio communication with mobile stations of subscribers in their cells.

 The network of station transceivers covers a certain territory with radio communication, served by one mobile switching center. In the Russian Federation, this is the territory of a region or region with a mobile switching center located in an administrative center.

 The disadvantage of the GSM system is that it does not provide the ability to directly connect to the public telephone network at the local level for remote areas of the served territory.

 The closest analogue to the present invention is a mobile cellular radio communication system NMT (Gromakov Yu.A. Standards and mobile radio communication systems. Electronic communications technology. T. 67. - M .: 1996, p. 67-75).

 The NMT network includes a mobile switching center, base stations, and mobile subscriber stations.

 A mobile switching center provides control of a mobile communication system and an interface with a public switched telephone network.

 Base stations are connected via communication channels to the mobile switching center and provide radio communication with mobile stations.

 The area in which one base station provides radio communications is called a cell. A network of base stations connected to a specific mobile switching center covers with radio communication a certain territory served by this mobile switching center.

 The system provides continuous communication and accessibility for mobile stations throughout the served territory.

 Usually, this is the territory of a region or region with a mobile switching center located in the administrative center, and base stations are located in settlements, along highways, in recreational areas, etc.

 Quite often, one or a group of base stations serves a geographic area that is substantially remote from the mobile switching center — a city, district, or even another regional center.

 The disadvantage of the NMT system is that it does not provide the ability to directly connect to the public telephone network at the local level for remote areas of the served territory.

The consequence of this drawback are:
- poor quality of communication between mobile subscribers in the remote zone and subscribers of the local exchange due to the large length of the channels;
- inaccessibility of mobile stations of subscribers on the part of subscribers of the local telephone exchange who do not have access to long-distance communication (pay phones, office automatic telephone exchanges, etc.);
- the need to use a large number of long-distance channels from a mobile switching center to remote areas;
- the use of long-distance communication during connections between mobile subscribers in remote areas and local telephone exchanges.

 The possibility of direct connection to the public telephone network at the local level for remote areas of the served territory is achieved by the fact that zone controllers are introduced into the cellular mobile communication system, which are connected between the mobile switching center and base stations and have an interface for connecting to the public telephone network use.

 Analysis of the known technical solutions showed that these differences are significant.

 The figure shows the structure of the proposed cellular mobile communication system (JCSS).

 The JCSS network includes a Mobile Switching Center (CSC) 1, which has an interface for connecting to a public telephone network, a zone communication controller (CLC) 2, base stations (BS) 3, and mobile stations of subscribers (PS) 4.

 A cellular mobile communication system operates as follows.

 TsKPS 1 provides control of the mobile communication system and interface with the public switched telephone network (PSTN).

 BS 3 are connected to CKPS 1 through KZS 2, which provide radio communication with PS 4.

 The territory served by one base station forms a cell. The territory serviced by a group of adjacent BS 3 connected to one KZS 2 forms the service area of this KZS 2. The zone communication controller provides control of the mobile subsystem within the served zone, closure of the internal load, and the interface with the PSTN local automatic telephone exchange (PBX). Controller 2 is connected to the CCHPS 1 as a base station, and the entire serviced zone for CCHPS 1 is seen as one cell. And base stations are connected to KZS 2 as well as to TsKPS 1.

 Messages from CCPS 1 are received in the controller, interpreted and, if necessary, modified messages are sent to external BS 3 and PS 4. And, conversely, messages from BS 3 and PS 4 are received and interpreted in CSC 2 and, if necessary, modified messages are sent to CCPS 1.

 Mobile stations registered in KZS 2 have two subscriber numbers.

 The first subscriber number is assigned to a specific Substation 4 as to any subscriber of the CPSS 1, and by this number it is available throughout the territory of the JCSS to any mobile or stationary PSTN subscriber.

 The second subscriber number is assigned to a specific Substation 4 as a subscriber of the local telephone exchange to which the controller is connected.

 It is considered advisable to install a GLC 2 for servicing zones remote from the location of the central distribution station 1 with connection to the PSTN in different zones.

 When a subscriber moves between cells, communication continuity and availability is provided by KZS 2, if the cells belong to one zone or CCPS 1 if the cells do not belong to one zone.

Outgoing calls from PS 4 in the zone of the GLC 2 are as follows:
- A call from SS 4 in the zone of KZS 2 to SS 4
In this case, GLC 2 by the number of the called mobile subscriber determines whether it is available in the served area, if yes, it makes a call through the corresponding BS 3 and performs switching for conversation. The internal connection does not require the participation of CCPS 1 and, accordingly, communication channels to CCPS 1 and vice versa are not used, as in other cellular communication systems. If the called mobile subscriber is out of range, the MSC 2 transmits the call to the MSC 1. After the MSC 1 has established a connection with the called subscriber, a conversation is made.

- A call from PS 4 in the zone of KZS 2 to a local telephone exchange subscriber
In this case, GLC 2 with the number of the called stationary subscriber determines that the call is directed to the subscriber of the local telephone exchange and makes a call to the corresponding subscriber via trunk lines with the telephone exchange, upon successful completion of the call, a connection is established for conversation, this type of connection is possible only in the system with the zone controller communications providing local PSTN connectivity.

- A call from PS 4 in the zone of KZS 2 to the PSTN subscriber
If it is determined by the number of the called stationary subscriber that it is not a local telephone exchange subscriber, then MSC 2 broadcasts the call to MSC 1, which transfers the call to the PSTN for further connection establishment.

 In the general case, any subscriber can be accessed both through the local telephone exchange and through the public network at the connection point of the central telephone exchange 1. The specific option will be determined by administrative decisions and the adopted numbering system.

Incoming calls to PS 4 in zone KZS 2 are carried out as follows:
In zone KZS 2 there can be two types of subscribers. These are subscribers of KZS 2 and subscribers of TsKPS 1, who are not subscribers of this KZS 2. Subscribers of both types are available through TsKPS 1 by number in the SSPS network.

 This is the case when a call from PS 4 to MLC 2 is received from CCCH 1.

 GLC 2 transmits a call in the served area and establishes a connection through the cell BS 3 location of the subscriber.

 KZS 2 subscribers are also available as local PBX subscribers. To do this, they have a second numbering as subscribers of the local telephone exchange.

 In this case, the call arrives through the local telephone exchange to KZS 2.

 GLC 2 makes a call to the subscriber in its area and, upon successful completion, establishes a connection. If the subscriber is outside the zone of the MSC 2, the call is transmitted to the MSC 1 to further search for the subscriber and establish a connection.

 The inclusion of the zone communication controller in the SSPS network according to the proposed scheme allows us to obtain a new significant feature: switching subscribers and connecting to the PSTN network at the local level, which improves communication quality, reduces the number of channels used in the network and makes mobile subscribers more accessible for stationary subscribers.

 There are various ways to implement a zone communication controller. An example implementation of a zone communication controller may be a base station controller BSC 124 / NMT.

 KBS 24 / NMT is a complex of hardware and software and consists of two blocks - a block of radio interfaces and a switching block.

 The switching unit contains complexes of connecting lines for connecting to the telephone exchange and an 8x8 PCM path switch operating under the control of a microcomputer based on the 1810BM85 processor.

 The block of radio interfaces contains a control computer, signal conversion devices and four-wire analog joints.

 The block of radio interfaces contains a control computer, signal conversion devices and four-wire analog joints. The control computer performs the functions of mobility management, radio system control, protocol processing on interfaces with base stations and a mobile switching center.

 The control computer is implemented on the basis of the processor 1810VM86. The conversion devices provide signaling transmission at a speed of 1200 bps and are implemented on digital signal processing processors TMS320C25. Four-wire analog joints connect base stations and a mobile switching center.

 There are RS232 interfaces for connecting a PC for technical operation. KBS 24 / NMT implements NMN-450 system interface protocols.

 The economic feasibility in building a cellular mobile communication system according to the invention can be considered by the example of the use of KBS 24 / NMT in Syzran, Samara region.

 The mobile switching center of the cellular system NMT-450 of the Samara Region is located in the city of Samara. In the city of Syzran, it is planned to install a base station on eight radio channels. At the same time, the capital, operating and rental costs of the Syzran - Samara canals in one year amount to 189.5 thousand dollars. If you install KBS 24 / NMT in Syzran, the capital costs will increase, but the channel rental fee will decrease and the result will hardly change - 187.5 thousand dollars. It should be noted that local calls make up 85%. In subsequent years, the costs of using KBS 24 / NMT will decrease from $ 119.5 thousand to $ 37.5 thousand.

 Thus, the introduction of a zone communication controller into the cellular mobile communication system gives a significant economic effect. At the same time, the indirect economic effect due to the improvement of the consumer qualities of the system was not taken into account.

Claims (1)

 A cellular mobile communication system comprising a mobile switching center having an interface for connecting to a public switched telephone network, base stations that are connected to a mobile switching center, and mobile subscriber stations having radio access to the system through base stations, characterized in that it introduced zone controllers, which are connected between the mobile switching center and base stations and have an interface for connecting to a public telephone network.