Multiplex communications – Communication over free space – Combining or distributing information via time channels
Patent
1997-04-14
2000-11-07
Ngo, Ricky
Multiplex communications
Communication over free space
Combining or distributing information via time channels
370311, 370350, 455 383, H04B 700, H04B 7212, G08C 1700
Patent
active
061446564
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a method for synchronizing a telecommunications connection in a mobile communications system comprising a database; at least one base station communicating with mobile stations on TDMA (Time Division Multiple Access) system channels consisting of control channels and traffic channels whose uplink and downlink frequencies are divided into frames a part of which may be defined dynamically, by means of determining an energy economy mode start frame and the length of an energy economy cycle, for a mobile station in said database as energy economy mode sleeping frames, during which said mobile station is not prepared to receive transmissions on downlink frequencies; at least a first mobile station communicating on a direct mode channel divided into frames and wishing to operate in a dual watch mode both on the control channel of the mobile communication system and on said direct mode channel which comprises pre-emption frames, by means of which the mobile stations communicating on said direct mode channel request transmission turns for themselves.
BACKGROUND OF THE INVENTION
The invention relates to the field of mobile telephone systems. A subscriber of a mobile telephone system, that is, a subscriber station, e.g. a mobile telephone or a mobile station may be connected to a mobile network or system, whereby it is connected to the mobile network via system channels maintained by the base stations of the mobile network.
In addition to the system channels located in mobile telephone systems, so-called direct mode channels may be used in association with the mobile system, i.e. communication takes place in a direct mode. Subscriber stations communicating in the direct mode do not communicate directly with the mobile network or the base stations related to it. Direct mode channels are frequencies on which mobile telephones or other means of communication can communicate without the system directly with each other, or via repeater stations, either with the base stations of the system or with other mobile stations.
Direct mode channels are typically used in situations in which e.g. a group of hand-held mobile phones communicate with each other so remote from the base stations that the use of system channels is not possible.
Another important use of direct mode channels is increasing the capacity when the traffic in the system rapidly increases (incident) in some part of the service area of the system, e.g. in some spot-like part.
A direct mode channel is a channel that is typically not used by the system. It may be e.g. a channel whose channel spacing is the same as that in the mobile communications system, e.g. 12.5 kHz or 25 kHz. On direct mode channels a mode of simplex operation is used. From the group of the mobile stations operating on the direct mode channel, the transmitting party has tuned his transmitter onto the channel and is transmitting speech or data information. The other mobile stations that have been activated onto the direct mode channel have tuned their receivers onto the same frequency so that they will directly hear the transmission.
On a direct mode channel, communication may take place by means of analog modulation or digital modulation. A mobile station transmitting on the channel may also use signalling information, such as information on access rights and priorities, or the group communicating on the channel, or data communication. On a direct mode channel encryption may be carried out, or plain speech can be transmitted.
Subscriber stations operating in the direct mode communicate with other subscriber stations on a direct mode channel without having a direct connection to the base stations of the mobile network. Subscriber stations operating in the direct mode, however, may communicate with the mobile network via repeater stations. A repeater station typically comprises two transceivers connected to each other.
The prior art solutions are attended by the problem how to make a mobile station operating in accordance with the dual watch fac
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Kinnunen Kimmo
Schroderus Osmo
Ngo Ricky
Nguyen Steven
Nokia Telecommunications Oy
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