Multi-mode radio telephone which executes handover between different system
First Claim
1. A radio telephone operable for more than one different radio telephone system having different operational protocols, comprising communication means respectively associated with each of the different radio telephone systems and control means for controlling the communication means, wherein a first communication means is responsive to the control means to automatically cease communication with a first radio system and a second communication means is substantially simultaneously responsive to the control means to automatically commence communication with a second radio system to effect handover of a call from a first radio telephone system to a second radio telephone system, wherein the telephone further comprises signal processing means adapted to inhibit sudden change in audio signals during handover.
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Accused Products
Abstract
A radio telephone automatically hands over a call from one radio telephone system to another radio telephone system. Communication with respective radio telephone systems may be simultaneously continued during handover until the handover is complete, or communication with one radio telephone system ceases before communication with the other radio telephone system commences. Delays between signals of different radio telephone systems which would cause audible interference are inhibited by FIR filtering and/or dynamic time-warping. If an handover fails then communication with the original radio telephone system is restarted or continued.
174 Citations
20 Claims
- 1. A radio telephone operable for more than one different radio telephone system having different operational protocols, comprising communication means respectively associated with each of the different radio telephone systems and control means for controlling the communication means, wherein a first communication means is responsive to the control means to automatically cease communication with a first radio system and a second communication means is substantially simultaneously responsive to the control means to automatically commence communication with a second radio system to effect handover of a call from a first radio telephone system to a second radio telephone system, wherein the telephone further comprises signal processing means adapted to inhibit sudden change in audio signals during handover.
- 11. A method of operating a radio telephone for more than one different radio telephone system having different operational protocols, comprising respectively communicating with each of the different radio telephone systems, automatically ceasing communication with a first radio system and automatically commencing communication with a second radio system for effecting handover of a call between respective radio systems, and wherein signal processing is utilized to inhibit sudden changes in audio signals during handover.
Specification