Telecommunications – Transmitter and receiver at same station – Radiotelephone equipment detail
Reexamination Certificate
1994-05-31
2001-07-10
Cumming, William (Department: 2684)
Telecommunications
Transmitter and receiver at same station
Radiotelephone equipment detail
Reexamination Certificate
active
06259929
ABSTRACT:
The present invention relates to a radio phone composable of separate modules, comprising a basic module and at least one additional module detachably plugged thereto.
BACKGROUND OF THE INVENTION
The subscriber numbers of mobile phone networks increase strongly every year; consequently, the capacity of analogue mobile phones is coming to an end in several countries in the course of the next few years. In addition, the analogue networks are frequently national. In order to solve the problems related to capacity and internationality, a general European GSM mobile phone network is being implemented. The GSM network is the first fully digital mobile phone network. Digital mobile phone networks are being established also in the US.
Installing new digital networks takes several years. Starting of a GSM network will begin in capitals and will gradually spread to form a network which covers the whole Europe. In the transition period, an existing analogue mobile phone network operating in the same frequency range can be used in parallel with the new digital network. Analogue networks operating in Europe in the same frequency range include NMT-900 in the Nordic countries and TACS in Britain. In the USA, the analogue AMPS network operates in the same frequency range, and the coming digital CDMA network as well as the dual-mode network.
In the analogue network the mobile phone receives and transmits an analogue signal; respectively, in the digital network, a digital signal. Thus, mobile phones provided for an analogue network cannot as such be used in digital networks of the same frequency range, and vice versa. Transition into new digital networks is almost indispensable since the analogue networks are overloaded. On the other hand, the new network is not very large at the very beginning, so that a parallel use together with the existing analogue networks would be desirable.
The problem of two networks can be solved in that a so-called dual-mode phone is specified which is able to operate both as a digital and an analogue phone. The dual-mode phone selects automatically either of the modes of operation to conform to the base station environment. For instance, in the future US dual-mode system this kind of phone is a necessity because also in digital mode, the paging channel trafficing is carried out in the channels of the AMPS system. In the digital systems as such, the dual-mode phone facilitates the transition period.
The dual-mode phone is larger in size and in weight than the single-mode phone so that it is unnecessarily bulky to carry when the user is located clearly in the range of operation of either the analogue network or the digital network. In the city centres where the analogue network is crowded, it is convenient to use the digital network, and in suburban areas where digital networks have not been initially installed, the analogue network has to be used.
SUMMARY OF THE INVENTION
The object of the invention is to provide an apparatus to be operable both in the form of single-mode and dual-mode phone. The phone would be operable in the current wide analogue network range in the form of a small-sized analogue phone, and in a crowded city area in the form of a small digital phone. It is expedient to use the phone as a dual-mode phone in areas in which the analogue and the digital networks overlap and when moving somewhat across a borderline of one of the networks into an area of another network because the phone automatically picks the mode of operation according to the services available. For instance, when moving beyond the coverage area of the digital network to an area where an analogue network already exists, the phone automatically shifts to the analogue mode of operation.
According to the present invention there is provided a radio telephone capable of dual-mode operation, comprising a basic module including circuitry common to the operation of the telephone in both modes, a first supplementary module including circuitry for processing signals characteristic of a first mode of operation, and a second supplementary module including circuitry for processing signals characteristic of a second mode of operation, wherein at least one of the first and second supplementary modules may be detachable coupled to the basic module such that the telephone is operable in the first and/or second modes according to which of the first and second supplementary modules is coupled to the basic module.
A telephone in accordance with the invention is thus operable in a first mode when the first supplementary module is in place, and in a second mode when the second subsidiary module is in place. A dual-mode of operation is possible if both the supplementary modules are present.
The first mode may correspond to an analogue mode or operation and the second mode to a digital mode of operation. Alternatively, the two modes of operation may relate respectively to different digital systems, e.g. a time division multiple access (TDMA) system and a code division multiple access system (CDMA).
In the dual digital mode embodiment the first supplementary module includes circuitry for processing digital signals associated with a first radio telephone system, and the second supplementary module includes circuitry for processing digital signals associated with a second radio telephone system.
In the analogue-digital dual-mode embodiment the first supplementary module includes circuitry for processing analogue signals associated with an analogue radio telephone system, and the second supplementary module includes circuitry for processing digital signals associated with a digital radio telephone system.
One of the supplementary modules may be provided integrally with said basic module. In this case the dual-mode of operation is enabled by attaching the other supplementary module to the basic module.
Alternatively, both said first and second supplementary modules respectively may be detachably coupled to the basic module. In this case either mode of operation may be enabled by attachment of the corresponding supplementary module. Suitably, one of the supplementary modules may be detachably coupled to the other supplementary module so that when both supplementary modules are attached, dual-mode operation is enabled.
Thus it can be seen that a telephone in accordance with the present invention offers maximum flexibility in view of the different telephone systems available, wherein the user can render the telephone operable on a particular system by attaching the appropriate supplementary unit to the basic module of the telephone.
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Cumming William
Nokia Mobile Phones Limited
Perman & Green LLP
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