Nokia Mobile Phones Limited

Nokia Corporation

Mika Jari Tuutijarvi

Raimo Tapio Klemetti

Eero Sakari Makikallio

Jorma Antero Savolainen

Ilkka J Niva

Hannu Pakonen

A method for operating a mobile station includes steps of (a) receiving a signal from a forward traffic channel and decoding the received signal using a first decoding technique to generate a first bit error rate (BER); (b) decoding the received signal using a second decoding technique to generate a second BER; (c) comparing the first BER to the second BER; and (d) declaring the received signal to be one of a FACCH message or user data depending on a result of the comparison. The method may include an additional step of verifying that the received signal contains a valid FACCH message type.

Mobile station employing CRC verification using decoding reliability and methods therefor

The invention is related to a method for improving handover in reception and transmission in a digital cellular mobile communication system including base stations and mobile stations, in which mobile station receives from a base station a handover command in the middle of speech reception or transmission on a first reception or transmission channel, whereby in the handover, the reception/transmission is changed to a second reception or transmission channel. Particularly the invention is related to mobile communication systems based on time division multiple access, in which transmission and reception occur in bursts in separate time slots. In the method according to the invention, speech is sampled, or, in transmission, it is A/D converted (32), and in reception, it is D/A converted (22) during the handover and stored in memory, e.g. in buffers, and taken into use in reception during the handover by D/A converting (24) it for a loudspeaker, and in transmission, by transmitting (34) it immediately after the handover. This method shortens the silent period in the handover.

Method for improving handover

The strength of the signal or carrier in one or more transfer channels near the receiving channel of a radio device operating in a radio telephone system is measured, for example, with a MAHO measurement. The measurement result is used to calculate the disturbance caused by the transfer channel to the receiving channel, and, based on the acquired result, the frequency response of a filter included by the receiver is adjusted, for example, by changing the width or slope of the passband.

Method and circuit for filtering disturbances in a radio receiver

In the method of this invention, a mobile station is constructed to receive predetermined signals from neighboring base stations as an indication of received signal strength. These signals are compared to the current traffic signal strength indicator and a resultant signal is calculated proportional to the differential signal strength. Only the current received signal strength indicator is transmitted to the base station in absolute value. All other indicators are reported as relative values.

Simplified mobile assisted handoff of signal between cells

A power control loop for a radio frequency transmitter includes a power control amplifier, an output and a detector that is coupled to the output for providing an output power signal indicative of output power from the power control loop. A controller generates at least first and second reference signals. A differential amplifier provides a control output that is indicative of a difference between the output power signal and a reference signal. A dual rate filter couples the control output to the power control amplifier so as to vary its gain. The dual rate filter exhibits a fast-reacting filter mode when the controller changes the reference signals to the differential amplifier and a slow-reacting filter mode when the controller applies the first reference signal to the differential amplifier. The fast filter mode enables rapid feedback of the control output to the power control amplifier.

Dual rate power control loop for a transmitter

In a wireless or cellular telephone system operated, for example, in accordance with the TIA/EIA IS-54 TDMA standard specification and frame structure, wherein RSS measurements in a Mobile Station of scanned communication channels are made in the slot intervals between the RX and TX slots to prepare for determining the gain (AGC) values needed in the receiver for a new channel identified over the current channel communicating with a Base Station, wherein slot interval measurements of the new channel signal strength are used to achieve a shorter handoff time in the Mobile Station and a more accurate initial AGC value in the receiver. The new channel signal strength is measured using the existing MAHO measurement procedure according to the IS-54 standard specification, or like procedure, and is performed in three slot intervals. The results of these measurements are used to determine the AGC value needed for the new radio channel. The handoff acknowledgement message is created, interleaved, and sent on the current channel during or after the measurement period.

Fast AGC setting using RSS (I) measurement procedure

A method, and apparatus for accomplishing the method, that causes the power of a narrow bandwidth signal to be spread to a wider bandwidth. The method operates by modulating the power of the spectral components that are located close to a carrier frequency. This reduces the DC component of a base band signal and correspondingly reduces the charging of a AC coupling capacitors in the base band circuitry. As a result, receiver recovery time is increased, and a more accurate signal strength estimate is made by a mobile telephone. In one embodiment of the invention a local oscillator signal (LO1) for an IF stage is first offset from a nominal frequency for an RF channel to be measured, and is then subsequently made equal to the nominal frequency. The variation in LO1 introduces phase noise which results in the modulation of the base band signal.

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Oulu, Finland

Mika Jari Tuutijarvi