Telecommunications – Transmitter and receiver at separate stations – Plural transmitters or receivers
Reexamination Certificate
1999-11-08
2003-09-02
Appiah, Charles N. (Department: 2682)
Telecommunications
Transmitter and receiver at separate stations
Plural transmitters or receivers
C455S574000
Reexamination Certificate
active
06615051
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a radio telecommunications terminal and in particular to a method and apparatus for optimising the power consumed by such a terminal. The invention is particularly suitable for use with digital systems.
An example of such a terminal is one for enabling a fixed telecommunication system, adapted for use with a public switched telephone network (PSTN), to operate over a wireless (e.g. radio) telecommunications network. The term “fixed system” as used herein is intended to mean a system of communication devices (e.g. telephones, facsimile machines, data devices) which are normally connected to a fixed local system. The communication devices themselves may be cordless and/or mobile and operate within the area local to the fixed system.
In telecommunications, the final drop from the local telephone exchange to a subscriber's terminal or private exchange is known as the “local loop”. Traditionally this comprised a network of copper-pair lines, which are expensive to install and to maintain. In densely populated areas and/or countries with low telephone penetration this approach is impracticable. Wireless Local Loop (WLL) is a modern alternative to the copper network. In WLL a wireless (for example radio or infrared) system makes up all or part of the transmission path between the subscriber and the local exchange.
WLL allows the flexible allocation and reallocation of network resources and also has reduced installation time compared with fixed line networks. Thus WLL is particularly suitable for: providing network services quickly to small businesses and residential customers; cutting the cost of the local loop in remote or rural areas; providing telephone services in areas where accelerated development is required by regulatory bodies; and flexibly providing telecommunications services for instance at temporary locations such as exhibitions etc.
Generally WLL terminals comprise a transceiver, an external power supply and an antenna. More particularly a WLL terminal comprises an RF section for receiving and transmitting RF signals via an antenna; an interface for connecting a subscriber device to the wireless local loop terminal; a baseband section for converting received RF signals into baseband signals for transmission to the subscriber device and converting received baseband signals into RF signals for transmission by the RF section; and a subscriber line interface circuit for providing network dependent characteristics e.g. the tones (ringing, dial, engaged (busy) etc.) which, in a fixed network, are conventionally provided by the local exchange. A WLL terminal is capable of supporting many forms of transmission, for example speech, fax or data, and has interfaces for connecting to appropriate devices. An example of a known WLL system is described in British Patent Application no. 2311696.
The WLL terminals are fixed terminals i.e. they are designed to be fixed within a user's premises or with respect to the network. The terminals are typically fixed to the walls in a user's premises or to the walls of buildings for public network coverage. WLL typically use microwave, cordless or cellular technologies to interact with a radio telecommunications network.
A WLL terminal provides the interface between a subscriber's fixed telecommunication system (e.g. a private network or local area network) and the radio telecommunications network. When a user makes or receives a call via the WLL terminal, the WLL terminal establishes an uplink to the radio telecommunications network. In radio systems the transmitting power of a terminal is variable so as to avoid interference between terminals within the telecommunications system. Conventionally WLL terminals initiate transmission at a defined maximum power level and then adjust the power level in accordance with control signals sent from a controller of the radio system.
Similarly a mobile terminal for radio telecommunications conventionally initiates transmission at a defined maximum power level and then adjusts the power level in accordance with control signals sent from a controller of the radio system. The controller specifies the maximum power level and transmits this to the terminal continuously both when the terminal is in a stand-by mode and when the terminal is active. In the GSM specification this maximum transmission power level for the terminal is set by the parameter MS_TXPWR_MAX_CCH. This parameter is defined by the controller and may be specific to a controller, base station or coverage zone.
SUMMARY OF THE INVENTION
In accordance with the invention there is provided a terminal comprising: an antenna for transmitting and receiving radio frequency signals; a radio frequency section that amplifies and demodulates a signal received by the antenna into a baseband signal and which modulates and amplifies a baseband signal received by the radio frequency section for transmission via the antenna; a processor to control the operation of the terminal; and memory for storing parameters and programs for use by the processor; wherein the terminal is arranged to store in the memory information relating to an uplink power level used in at least one transmission and to use this information to initiate a subsequent transmission.
Thus the power level used when establishing a connection with a radio telecommunications network is optimised. This aims to reduce the power consumed by the terminal and also to prevent interference between the terminal and a subscriber device connected to the terminal. Interference between terminals within a coverage area is also reduced. Using lower power levels during a transmission may also result in more efficient re-use of transmission channels in neighbouring coverage areas.
Preferably the information relates to the immediately previous transmission and most advantageously to the maximum power level used in a previous transmission. The information may relate to the power level used in more than one e.g. three previous transmissions.
The terminal may be a wireless local loop terminal or a cellular radio telephone handset.
In accordance with a further aspect of the invention there is provided a method of controlling the power used by a radio terminal, the method comprising: transmitting a message to a radio telecommunications network; adjusting the power level of the transmitted message in accordance with control messages from the radio telecommunications network; storing information relating to the power level used during the transmission; and using the power level information to set the transmission power level to be used when initiating a subsequent transmission.
According to a further aspect of the invention there is provided apparatus for enabling a telephone system, adapted for use with a public switched telephone network, to operate over a radio telecommunications network, the apparatus comprising:
an antenna for transmitting and receiving radio frequency signals;
a radio frequency section that amplifies and demodulates a signal received by the antenna into a baseband signal and which modulates and amplifies a baseband signal received by the radio frequency section for transmission via the antenna;
a processor to control the operation of the terminal; and
memory for storing parameters and programs for use by the processor; wherein the terminal is arranged to store in the memory information relating to a power level used in at least one transmission and, when such information is stored, to use this information to initiate a subsequent transmission.
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Antonelli Terry Stout & Kraus LLP
Appiah Charles N.
Nokia Mobile Phones Limited
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