Hewlett-Packard Company

Jan Schiefer

Steven Nicholas Bennett

David Bonner

David Arthur Stephenson

Daniele Abbadessa

David Alan Clarke

A method and apparatus are provided 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, the network broadcasting to all mobile stations within each cell a frequency allocated to the cell by the network operator and a code allocated to the cell by the network operator. The allocated frequency and code for each cell are determined by monitoring signalling messages passed between network elements, selecting a pair of signalling messages in accordance to predetermined selection criteria, establishing if the pair of messages are related to the same event within the network, and if so, extracting data from the pair of messages. A first embodiment determines the beacon frequency and BSIC of a cell of a GSM type cellular network and associates them with a TRX within the cell. A second embodiment associates the Cell Identity of a cell of a GSM type cellular network with the determined beacon frequency and BSIC.

Network discovery method and apparatus for cellular mobile radio networks

In a mobile radio network such a GSM network, an operative identity code is passed by a mobile station to the fixed network part at the start of each communication transaction. This operative identity code will either be the unique identity code (IMSI) assigned to the mobile-station user or, more usually, a temporary, substitute, identity code (TMSI) allocated by the fixed network part with a view to obscuring the identity of the user to anyone monitoring the network radio traffic. Whilst the fixed network infrastructure knows the association between a temporary identity code (TMSI) and the corresponding unique identity code (IMSI) of a user, this information is generally not readily accessible. To enable the current temporary identity code (TMSI) of a user to be readily tracked without burdening the network infrastructure, a monitoring arrangement is provided which monitors network signalling messages to link the different messages associated with a particular user mobile station that separately give the current operative identity code (line 'c') and assign a successor operative identity code to that user (line 'h'). In one embodiment applicable to a GSM network, messages on the A interface that carry identity code information for a particular user during a communication transaction are linked through the local references of the SCCP connection established for the transaction. In a second embodiment, also applicable to GSM, messages on the Abis interface are monitored and linked through the channel numbers contained in these messages.

Method and apparatus for tracking identity-code changes in a

A method is provided of following a communication transaction during which a communicating mobile station (12) is handed-over from one radio cell to another in a mobile radio system. The transaction is followed across the handover by monitoring signaling messages on the signaling paths in the mobile radio system to detect the occurrence of common parameters related to communication transactions subject to handover. By correlating these parameters it is possible to associate fragments of the same transaction that give rise to signaling messages on different signaling paths. Thus in the case of a GSM mobile radio system with monitoring of the A interfaces, the parts of a communication transaction split by a handover from one BSC (17A) to another (17Z), can be associated by correlating the RR3 Handover Command signaling units appearing on the signaling links (68,69) to the old and new BSCs (17A,17Z). This correlation can conveniently be done at a central station (42) to which the signalling path monitors (40A,40Z) send report messages when they detect handovers occurring. A similar correlation can also be done when monitoring the Abis interfaces.

Handover following in a mobile radio system

A network discovery method is provided for determining the functionality existing at the nodes of a signalling network. Such a network typically comprises a plurality of nodes (BSC, MSC, GSMC, HLR, VLR, EIR) each exhibiting one or more types of functionality, and point-to-point links inter-connecting the nodes and carrying messages exchanged between nodes, the messages having characteristics dependent on the nature of the functionality of the nodes between which they are exchanged. The discovery method involves using probes and a central station to monitor one or more links and to identify from at least one message associated with a particular node, a predetermined set of message characteristics sufficient to identify a type of node functionality possessed by that node. The predetermined set of message characteristics may be derived from a single message, from several messages on the same or different links, or by observing the message transfer characteristics of the node concerned.

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Bristol, United Kingdom

Jan Schiefer