Alcatel

Xavier Dugast

Arnaud Parisel

Ulrich Barth

Christoph Sperber

Philippe Desblancs

Edgar K&uuml;hn

To address the problem of aging and drift of a local oscillator in a mobile telephone the frequency Fi of the local oscillator is shifted upwards so that base station logging-on FCH signals are measured perfectly whether said drift is upwards or downwards. It is shown that the actual drift resulting from the initial shift and drift with time can be measured during logging on. It is shown that conforming to the standard is facilitated without having to provide an oscillator whose frequency stability with time is guaranteed.

Telephone with a demodulator circuit with an improved local oscillator

To save energy and to increase the standby time and talk time of a mobile telephone, the activity of the mobile telephone is segmented, even during standby periods, and activation is allowed to occur only if the reception quality of signaling surrounding the standby condition is sufficient. When the mobile telephone is on standby, given the redundancy of the activation signaling, only some of the signals are listened to in order to decide whether it is necessary to listen to the others and to activate the mobile telephone. When the mobile telephone is communicating and the other party is silent, the energy consumed in receiving and above all in decoding the received signals is reduced by eliminating demodulated signals of too poor quality.

Method of receiving voice signals by a mobile telephone

Wireless telecommunications systems with at least one base station and with mobile user terminals are known where radio signals are transmitted and received in different time and frequency states. Both on user channels as well as on signaling channels there are radio signals that are transmitted corresponding to the predicted frequency hopping sequence. We now suggest, first, that the base station and the user terminal contain controllers (CTR) to control the frequency state alternation that produce no frequency hopping sequences for the first part of the time grid but rather predict a steady frequency (f ) and produce a pseudorandom frequency hopping sequence (THS) for at least one further part of the time grid after one iterative process (LGNR), second, that the base station transmits an input value (CW) to the user terminals in order to process the pseudorandom frequency hopping sequence, and to control the frequency alternation in accordance with this pseudorandom frequency hopping sequence in the controller for registering user terminals. This way we can achieve the result that a processed frequency hopping sequence is used as early as during transmission of registration signals, i.e. a frequency hopping sequence that is developed on the basis of the input value and does not have to be saved completely.

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Chatou, France

Xavier Dugast