Telecommunications – Radiotelephone system – Zoned or cellular telephone system
Reexamination Certificate
1999-01-26
2001-10-09
Trost, William G. (Department: 2683)
Telecommunications
Radiotelephone system
Zoned or cellular telephone system
C455S422100, C455S435100
Reexamination Certificate
active
06301475
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wireless local loop. In particular, the present invention relates to a procedure for limiting the mobility or usability of a terminal device in a wireless local loop environment, as defined in the preamble of claim
1
.
2. Description of Related Art
In a wireless local loop (WLL), a terminal device is connected via a radio link to an access node. Between the terminal device and the access node there is a base station, by means of which the call signals received via radiocommunication from the terminal device are further transmitted through the access node to the public telephone network and vice versa. The access node is connected to the telephone exchange using the V
5
.
2
protocol. The mobility area (MOA) of a terminal device is a geographic area within which the terminal device may be connected to a wireless local loop and outside which the terminal device cannot be connected to the local loop. The mobility area defines the mobility area of a terminal device within the wireless network comprised by an access node. Mobility of a terminal device between the access nodes of a WLL operator is inhibited because subscriber information is only defined in a single access node. A terminal device cannot be locked with a public GSM network because the WLL operator has its own network identifier and no roaming agreement with GSM operators.
Open interfaces (V
5
.
1
and V
5
.
2
) between an access node and a telephone exchange are defined in the ETSI (European Telecommunications and Standards Institute) standards of the ETS 300 324 and ETS 300 347 series. V
5
interfaces enable subscribers belonging to a physically separate local loop to be connected using the standard interface of a telephone exchange. A dynamic concentrator interface V
5
.
2
consistent with the standards ETS 300 347-1 and 347-2 consists of one or more (1-16) PCM (Pulse Code Modulation) cables. One PCM cable comprises a total of 32 channels, each of which with a transfer rate of 64 kbit/s, i.e. 2048 kbit/s in all. The V
5
.
2
interface supports analogue telephones as used in the public telephone network, digital subscriptions, such as ISDN (Integrated Services Digital Network) basic and system subscriptions as well as other analogue or digital terminal equipment based on semi-fixed connections.
There are prior-art wireless telephone networks, an example of which is the digital GSM mobile telephone network, in which voice or sound signals or other corresponding data are transmitted using systems based on the ISDN (Integrated Services Digital Network) technology. In the GSM mobile telephone system, a terminal device may work in the entire area of the network, i.e. the terminal device may get locked, perform channel changes and other actions in the area of any cell. However, in a wireless local loop environment, a desired feature is the ability to accurately determine, e.g. via actions by the network operator, the area in which a mobile terminal device connected to the system via a wireless link can be used. A problem with prior-art networks is that the mobility area cannot be delimited. A further problem is that current systems provide no means for delimiting the mobility area for each individual terminal device.
SUMMARY OF THE INVENTION
The object of the present invention is to eliminate the problems described above. A specific object of the present invention is to present a wireless local loop system in which a new radio network level has been defined. A further object of the present invention is to produce a procedure for controlling a wireless local loop in a way that allows the mobility area for each terminal device to be accurately defined.
In the procedure of the present invention for limiting the mobility area of a terminal device in a wireless local loop environment, which comprises an access node connected to a telephone exchange and a base station having a coverage area comprising one or more cells and used to transmit call signals between the access node and the terminal device, according to the invention, the mobility area for the terminal device is defined as a specified geographic area comprising the coverage area of at least one cell and, further according to the invention, locking with the local loop and/or channel change by the terminal device is inhibited if the cell with which the terminal device is attempting to get locked/to whose channel it is trying to change is outside the mobility area. The cell to whose channel the terminal device is trying to change is called the target cell. The connection between the access node and the telephone exchange, which is an access node V
5
interface consistent with the V
5
standard, is preferably implemented using signalling consistent with the V
5
standard.
Further, in a preferred embodiment, at the wireless network level, a specified geographic area is defined as the location area (LA), which corresponds to the coverage area of one cell, and the location area is assigned an individual identification code. Thus, since the location area always contains only one cell, accurate information is obtained as to the cell from which the terminal device is trying to get locked with the network or the cells from/to which it is trying to change channels. Further, the mobility area preferably comprises one or more location areas. Therefore, the mobility area is a new wireless network level, consisting of location areas.
In conjunction with the definition of the mobility area, data identifying the location areas comprised in the mobility area are stored in a register corresponding to the terminal device. In this way, the operator can create for each terminal device belonging to the system a unique mobility area which is independent of other terminal devices or their mobility areas.
Further, in a preferred embodiment of the present invention, when a terminal device is being initialized, the cell data for the location area of the terminal device are compared with the cell data stored in the register corresponding to the terminal device and, if the cell data for the location area are inconsistent with the cell data stored in the register corresponding to the terminal device, the initialization of the terminal device is terminated and the cell data for the location area are stored in an inhibition cell register in the terminal device. In this context, initialization refers to the initial actions performed by the terminal device at switch-on to establish connection with the base station and determine the parameters needed for the connection. Correspondingly, when the terminal device is initializing a channel change, the cell data for the target cell to which a channel change is being attempted are compared with the cell data in the register corresponding to the terminal device and, if the cell data for the target cell are inconsistent with the cell data in the register corresponding to the terminal device, the channel change to the target cell, initialized by the terminal device, is inhibited and the cell data for the target cell are stored in an inhibition cell register in the terminal device. Storing the cell data for the inhibition cells in an inhibition cell register in the terminal device has a significant effect towards reducing the number of initialization and channel change signals transmitted in the system.
Further, in conjunction with the initialization of the terminal device, the cell data for the location area of the terminal device are compared with the inhibition cell register in the terminal device and, if the location area cell data correspond to the cell data in the inhibition cell register, initialization of the terminal device is terminated. A corresponding comparison is performed in conjunction with a channel change initialized by the terminal device and, if the cell data for the target cell correspond to the cell data in the inhibition cell register, no channel change is attempted.
The mobility area of a terminal device is preferably defined in conjunction with the i
Saarela Petri
Sarpola Jussi
Altera Law Group LLC
Gesesse Tilahun
Nokia Networks Oy
Trost William G.
LandOfFree
Procedure for limiting the mobility area of a terminal... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Procedure for limiting the mobility area of a terminal..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Procedure for limiting the mobility area of a terminal... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2557917