Telefonaktiebolaget Lm Ericsson (publ)

Ericsson Gmbh

Bjorn O Ekelund

Bengt Lindoff

Joakim Axmon

Peter Alriksson

Paul W Dent

Nils Rutger Rydbeck

Anders Khullar

Patrik Olsson

Robert Hed

Lars A Jonsson

Anders E Edlund

A network node of a terrestrial cellular system provides telecommunications service to a user equipment (UE) in an airborne aircraft. Navigation information transmitted from the aircraft is periodically acquired, including aircraft identity, position, altitude, and a time of determining aircraft position. A link is maintained between the network node and the UE by transmitting beam steered, Doppler shift compensated downlink signals, and by performing beam steered reception of uplink signals. Beam steering is directed toward the aircraft based on the navigation information. Doppler shift compensation is adapted to compensate for a Doppler shift such that the UE experiences a nominal carrier frequency when receiving transmissions from the antenna nodes. Handover from a first to a second coverage area includes using a same cell identifier and a same frequency allocation in the second coverage area as are used in the first.

In-flight cellular communications system coverage of mobile communications equipment located in aircraft

A network node in a cellular telecommunications system hands over responsibility for serving a wireless communication equipment from a serving cell to a target cell, wherein the wireless communication equipment is situated in a first aircraft that is in-flight. An aircraft position, an aircraft velocity, and an aircraft direction are determined. For each candidate cell of a number of candidate cells, a level of beam distortion that would result from a beam directed from the candidate cell to the first aircraft is predicted. The target cell is selected from the candidate cells by identifying which of the candidate cells has a least amount of predicted beam distortion. The target cell is then signaled to prepare for a handover of responsibility for serving the wireless communication equipment.

Cell selection for airborne mobile cellular communications equipment

A portable telecommunication apparatus ( ) has a user interface ( ), a programmable controller ( ), a memory ( ) coupled to the controller, and an information access program ( ), such as a WAP browser, which is stored in the memory and is executable by the controller. The information access program provides access for a user to a global information network, such as Internet, through the user interface and a first wireless communication link. The apparatus also has an external device interface ( ) for connecting an external device to the portable telecommunication apparatus over a second communication link. The information access program ( ) allows the user to control the external device through the user interface ( ), the external device interface ( ) and the second communication link.

Portable telecommunication apparatus for controlling an electronic utility device

Methods and systems for generating timing signals in remote units which can be used in a radiocommunication system are described. A high accuracy clock can be used to provide a timing reference signal for a processor in the remote unit during times when highly accurate timing signals are required. During periods of low activity, the high accuracy clock can be turned off and a low accuracy clock can be used to generate the reference timing signals for the processor. Periodically, the accuracy of the low accuracy clock can be checked by determining a number of low accuracy clock pulses which are generated between system timing signals created based upon the high accuracy clock pulses. In this way, when the low accuracy clock is relied upon to create the system tuning signals, the accuracy is sufficient to enable the processor to recognize when it is time to again power up the high accuracy clock. Moreover, checking the accuracy of the low accuracy clock enables the processor to provide error compensation signals to a real time clock function which relies upon the low accuracy clock pulses for determining a current time.

Method and apparatus for reducing power consumption in a mobile radio

A digital system accommodates analog communications, thus avoiding the need for separate subsystems each dedicated to either analog or digital communications. The system includes a receive circuit for converting received signals into an intermediate frequency, a transmit circuit for modulating and transmitting signals and signal processors for processing the intermediate frequency signals and the signals to be transmitted, wherein the signals can be processed into digital or analog format using substantially the same circuitry.

Multi-mode signal processing

A method and system for compressing and decompressing voice messages in conjunction with storage thereof. By utilizing existing compression hardware and software, additional voice message features can be provided in mobile radio units with minimal expense and system disruption.

Mobile phone having voice message capability

The invention relates to the selection of an antenna in a receiver of a mobile radio station which forms part of a time-multiplexed radio communication system. The signal strength of each antenna is measured in each time slot which immediately precedes the time slot intended for the station concerned, and the antenna selection is effected in dependence on the measured signal strengths. In order to eliminate the risk of unsuitable antenna selection as a result of momentary falls in signal strength, the signal strength for each antenna is measured on several occasions during the time slot in which the measurements take place. The signal-strength values for each antenna are thereafter combined linearly, so as to form a suitability measurement. The antenna having the highest suitability measurement is selected for the next arriving time slot.

Method of selecting the most suitable receiver antenna from two or more

A method for compensating for non-linearities in an end amplifier (F) having a given transfer function H.sub.R, H.sub..phi. for amplitude and phase respectively and included in a radio transmitter of quadrature type for linear, digital modulation, and in which table look-up units (ST, CT) store the digital sine and cosine values (I(t,.alpha.), Q(t,.alpha.)) of the quadrature components determined by a given signal vector .alpha.. According to the method of values of the transfer functions H.sub.R, H.sub..phi. for the quadrature modulated radio signals r(t,.alpha.) are calculated by addressing memory units (MH1, MH2) which store a number of values of H.sub.R and H.sub..phi.. The sine and cosine values of the addressed values of H.sub.R and H.sub..phi. are also formed. The thus calculated values are multiplied by the stored digital values in the table look-up units (ST, CT) and by the inverted value of H.sub.R. As a result, new modified values i(t,.alpha.), q(t,.alpha.) are obtained for the quadrature components, which compensates for the non-linearities in the final amplifier.

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Lund, Sweden

Bjorn O Ekelund