Apparatus and method for data transmission to inhibit radio signal fading with sequential transmission of data groups based upon power levels

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION Embodiments of the present invention will now be described by way of example only, and with reference to the accompanying drawings.
FIG.
1 shows a diagrammatic representation of a cellular radio telephone network such as a GSM network.
Mobile Switching Centre (MSC) 101 is associated with Base Station Controllers (BSC) 102 for controlling the Base Transceiver Stations (BTS) 103.
Typically, an MSC 101 is responsible for a number of radio telephone cells which would cover an urban area and its immediately adjacent environment.
Each BTS 103 comprises both a receive antenna and a transmit antenna for communicating with a radio telephone 104.
It is possible for a BTS 103 and a BSC 102 to be at the same geographical location and within the same housing.
The radio telephone 104 may be a mobile unit installed in a vehicle, a so called transportable unit or a hand held portable unit.
The radio telephone 104 comprises an antenna for receiving and transmitting information between the radio telephone 104 and the BTS 103, a transceiver, a keypad and display.
Such features and others are conventionally found in a radio telephone 104, and since these aspects are not directly relevant to the instant invention no further details will be given here, except to say that a microprocessor is employed to control the basic functions of the radio telephone 104.
Alternatively, the telephone functions may be controlled by a master microcomputer, while the keypad and display functions are under the control of a separate slave microcomputer coupled to communicate with the master microcomputer.
As described earlier, the output power level of a radio telephone 104 can be varied in response to requests from a base station BTS 103.
Typical apparatus for performing such control in a radio telephone 104 is shown in FIG.
2.
The transmitter power output stage of the radio telephone 104 comprises a power module 201 including a voltage controlled variable gain amplifier 202