Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1998-11-18
2001-05-22
Woo, Stella (Department: 2643)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S517000, C455S067150
Reexamination Certificate
active
06236856
ABSTRACT:
DESCRIPTION
This invention relates to a method of and an apparatus for determining information about cellular mobile radio networks. The invention is applicable to GSM networks, which in the context of this specification is to be taken to include, for example, DCS1800 and PCS1900 networks, and also to other non-GSM networks.
In particular, a first aspect of the present invention relates to a method of determining information about a cellular mobile radio network comprising a fixed part providing radio coverage in a plurality of cells and mobile stations for communicating with the fixed part across a radio interface, each cell using a group of control channels which are configured in accordance with configuration messages which are passed in the network when the cell is to be configured or reconfigured.
As will be described in detail below, in a GSM network, the control channel group configuration parameters are known as CCCH_CONF, BS_AG_BLKS_RES and BS_PA_MFRMS, and they are passed on the Abis interface between a base station controller and a base transceiver station in messages such as the BCCH INFO, SACCH FILL and SACCH INFO MODIFY messages when a cell configuration or reconfiguration takes place. An operator might also decide to send these messages occasionally at other times. It would be desirable to be able to monitor the Abis interface to determine these control channel configuration parameters. They can be used to determine the cell capacity and can be combined with traffic data to build up precise information about the usage of the cell, traffic load and patterns, etc. However, cell configuration or reconfiguration seldom takes place.
The present invention is concerned more particularly with a technique for determining information about the control channel group configuration without having to wait until a cell reconfiguration takes place.
In accordance with the first aspect of the invention, the method of determining information about a cellular mobile radio network comprises the steps of: monitoring signalling messages of a cell (preferably at the Abis interface in the case of GSM) which are passed in the network generally more frequently than the configuration messages; detecting one of the monitored messages which is of a first predetermined type; and extracting information from the detected message relating to the control channel group configuration of the cell. In its broad form, this aspect of the invention does not necessarily enable all information about any control channel group configuration to be obtained. However, the information can be obtained without having to wait for a cell reconfiguration.
In the case where the first type of message contains information sufficient to determine some of the control channel group configuration information, but which is insufficient to determine the control channel group information for all of the control channel groups, the method preferably further includes the steps of: detecting at least one other of the monitored messages which is of another predetermined type; and extracting further information from the other detected message relating to the control channel group configuration of the cell.
In the case where the radio interface employs time division multiple access, the detected message (or at least one of the detected messages) may be one which includes an indication of a timeslot number for a timeslot in which the message is to be sent, or was received, across the radio interface, and in this case the extracting step for the type of message (or at least one of the types of message) preferably includes the steps of: extracting the timeslot number from the detected message; and testing its value. In the case of a GSM network, the last-mentioned type of message may be, for example, a CHAN RQD, CHAN ACTIV, EST REQ, PAGING CMD, SMSBREQ or SMSBC message, as defined by GSM standard 08.58.
Also in the case where the radio interface employs time division multiple access, the detected message (or at least one of the detected messages) may, alternatively or additionally, be one which includes an indication of a frame number of the message, and in this case the extracting step for the type of message (or at least one of the types of message) preferably includes the steps of: extracting the frame number, or a component of it, from the detected message; and testing its value. In the case of a GSM network, and the last-mentioned type of message may be, for example, a CHAN RQD message.
Alternatively or additionally, the detected message (or at least one of the detected messages) may be one which includes an indication of a channel type on which the message is to be sent, or was received, across the radio interface, and in this case the extracting step for the type of message (or at least one of the types of message) preferably includes the steps of: extracting the channel type from the detected message; and testing its value. In the case of a GSM network, the last-mentioned type of message may be, for example, a CHAN ACTIV, EST REQ, SMSBREQ or SMSBC message.
As will be described in more detail below, with the above features, the extracted information can be used to determine whether the cell has Group iv, Group v or Group vi control channel configuration, as specified in GSM standard 05.02.
Alternatively or additionally, the detected message (or at least one of the detected messages) may be one which includes an indication of a paging group to which one of the mobile stations belongs, and in this case the extracting step for the type of message (or at least one of the types of message) preferably includes the steps of: extracting the paging group from the detected message; and keeping track of the highest paging group so extracted. In the case of a GSM network, the last-mentioned type of message may be a PAGING CMD message.
In accordance with a second aspect of the present invention, there is provided a corresponding apparatus for determining information about a cellular mobile radio network comprising a fixed part providing radio coverage in a plurality of cells and mobile stations for communicating with the fixed part across a radio interface, each cell using a group of control channels which are configured in accordance with configuration messages which are passed in the network when the cell is to be configured or reconfigured, the apparatus comprising: means for monitoring signalling messages of a cell which are passed in the network generally more frequently than the configuration messages; means for detecting one of the monitored messages which is of a first predetermined type; and means for extracting information from the detected message relating to the control channel group configuration of the cell.
REFERENCES:
patent: 5648962 (1997-07-01), Pirinen
patent: 6091950 (2000-07-01), Remy
patent: 738091A1 (1996-10-01), None
Pautet et al., GSM protocol architecture: radio subsystem signalling, May 19, 1991.*
European Search Report, EP 97 30 9515, Apr. 20, 1998.
Revista Espanola De Electronica, No. 488-489, Jul. 1995, pp. 36-41 B. Schoeppe, “Equipos de Prueba para la Interfaz GSM A bis”.
ITG-Fachberichte, No. 124, Sep. 1, 1993, pp. 423-432, Fingerle, B-M, “GSM Signalisierung in der Praxis”.
Hewlett--Packard Company
Ramakrishnaiah Melur
Woo Stella
LandOfFree
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