Method for improving handover
First Claim
1. A method for improving handover in reception in a digital cellular mobile communication system which includes base stations and mobile stations in which transmission and reception occur in bursts in separate time slots and in which one of said mobile stations receives from one of said base stations a handover command in the middle of speech reception on a first reception channel, whereby in the hand-over, reception is changed to a second reception channel, wherein, during the handover, communication of voice signals between said one mobile station and said one base station via said first channel is cut off prior to inception of communication via said second channel, the method comprising steps of:
- in the mobile station, decoding into digital samples the last completely received speech burst over said first channel preceding the handover command; and
during the handover, converting by D/A said digital samples and reproducing said digital samples on a loud speaker of the mobile station.
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Accused Products
Abstract
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.
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Citations
8 Claims
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1. A method for improving handover in reception in a digital cellular mobile communication system which includes base stations and mobile stations in which transmission and reception occur in bursts in separate time slots and in which one of said mobile stations receives from one of said base stations a handover command in the middle of speech reception on a first reception channel, whereby in the hand-over, reception is changed to a second reception channel, wherein, during the handover, communication of voice signals between said one mobile station and said one base station via said first channel is cut off prior to inception of communication via said second channel, the method comprising steps of:
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in the mobile station, decoding into digital samples the last completely received speech burst over said first channel preceding the handover command; and during the handover, converting by D/A said digital samples and reproducing said digital samples on a loud speaker of the mobile station. - View Dependent Claims (2, 3, 4)
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5. A method for improving handover in transmission in a digital mobile communication system which includes base stations and mobile stations, in which transmission and reception occur in bursts in separate time slots and in which one of said mobile stations receives from one of said base stations a handover command in the middle of speech transmission on a first transmission channel, whereby in the handover, transmission is changed to a second transmission channel on which the transmission continues after the mobile station has been synchronized to said second transmission channel, wherein, during the handover, communication of voice signals between said one mobile station and said one base station via said first channel is cut off during the handover prior to inception of communication via said second channel, the method comprising steps of:
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during the hand-over, sampling an analog speech signal communicated via said first channel into digital speech samples in the mobile station; and after the mobile station has been synchronized to said second transmission channel, encoding and transmitting said digital speech samples. - View Dependent Claims (6, 7, 8)
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Specification