Method and system for preventing call drop by limiting search time of 1x system during 1x ev-do system traffic state
First Claim
1. A system for preventing a call drop from occurring between a CDMA 2000 1xEV-DO (Evolution-Data Optimized) system and a hybrid access terminal in traffic with the CDMA 2000 1xEV-DO system, by limiting a predetermined search time for a 1X system, the system comprising:
- the hybrid access terminal operated in a 1X mode in relation to the 1X system for receiving a voice signal transmission service or a low-rate data transmission service from the 1X system and in a 1xEV-DO mode in relation to the 1xEV-DO system for receiving a high-rate data transmission service from the 1xEV-DO system, the hybrid access terminal in traffic with the 1xEV-DO system being periodically switched into the 1X mode so as to update overhead messages and returned to the 1xEV-DO mode if the predetermined search time lapses;
a base station transceiver subsystem including a 1xEV-DO access network transceiver for transmitting/receiving packet data to/from the hybrid access terminal and a 1X transceiver for transmitting/receiving voice or data to/from the hybrid access terminal;
a base station controller including a 1xEV-DO access network controller for controlling a packet data transmission service of the 1xEV-DO access network transceiver and a 1X controller for controlling a transmission service of the 1X transceiver; and
a packet data serving node (PDSN) connected to the 1xEV-DO access network controller so as to transmit/receive the packet data to/from the 1xEV-DO system.
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Accused Products
Abstract
Disclosed is a method and a system for preventing a call drop by limiting a search time for a 1X system during a 1xEV-DO system traffic state. The system comprises a hybrid access terminal, supporting both a 1xEV-DO system and a 1X system, for periodically switching over to the 1X system while in traffic with the 1xEV-DO system, updating an overhead message, checking a search time and switching over to the 1xEV-DO system based on a result of the search time; a base station transceiver subsystem including a 1xEV-DO transceiver subsystem for exchanging a packet data with the hybrid access terminal and a 1X transceiver subsystem for exchanging a voice or data with the hybrid access terminal; a base station controller including a 1xEV-DO controller for controlling a packet data transmission service of the 1xEV-DO transceiver subsystem and a 1X controller for controlling transmission service of the 1X transceiver subsystem; and a packet data serving node connected to the 1xEV-DO controller for exchanging the packet data with the 1xEV-DO system.
33 Citations
25 Claims
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1. A system for preventing a call drop from occurring between a CDMA 2000 1xEV-DO (Evolution-Data Optimized) system and a hybrid access terminal in traffic with the CDMA 2000 1xEV-DO system, by limiting a predetermined search time for a 1X system, the system comprising:
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the hybrid access terminal operated in a 1X mode in relation to the 1X system for receiving a voice signal transmission service or a low-rate data transmission service from the 1X system and in a 1xEV-DO mode in relation to the 1xEV-DO system for receiving a high-rate data transmission service from the 1xEV-DO system, the hybrid access terminal in traffic with the 1xEV-DO system being periodically switched into the 1X mode so as to update overhead messages and returned to the 1xEV-DO mode if the predetermined search time lapses;
a base station transceiver subsystem including a 1xEV-DO access network transceiver for transmitting/receiving packet data to/from the hybrid access terminal and a 1X transceiver for transmitting/receiving voice or data to/from the hybrid access terminal;
a base station controller including a 1xEV-DO access network controller for controlling a packet data transmission service of the 1xEV-DO access network transceiver and a 1X controller for controlling a transmission service of the 1X transceiver; and
a packet data serving node (PDSN) connected to the 1xEV-DO access network controller so as to transmit/receive the packet data to/from the 1xEV-DO system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for preventing a call drop from occurring between a CDMA 2000 1xEV-DO (Evolution-Data Optimized) system and a hybrid access terminal in traffic with the CDMA 2000 1xEV-DO system, by limiting a predetermined search time for a 1X system, the method comprising the steps of:
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(a) sequentially initializing a 1X mode and a 1xEV-DO mode of the hybrid access terminal such that the hybrid access terminal stays in an idle state;
(b) alternately and periodically performing monitoring with respect to the 1X system and the 1xEV-DO by using the hybrid access terminal in a state that the hybrid access terminal stays in the idle state;
(c) allowing the hybrid access terminal to enter a traffic state of the 1xEV-DO mode such that a connection and a session are formed between the hybrid access terminal and the 1xEV-DO system, thereby enabling the hybrid access terminal to transmit/receive packet data to/from the 1xEV-DO system;
(d) switching the hybrid access terminal into the 1X mode if a predetermined monitoring time lapses;
(e) checking a switching time and detecting signals of the 1X system when the hybrid access terminal is switched into the 1X mode; and
(f) allowing the hybrid access terminal to return to the 1xEV-DO mode if the switching time reaches a predetermined return start time. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A hybrid access terminal for preventing a call drop from occurring between a CDMA 2000 1xEV-DO (Evolution-Data Optimized) system and the hybrid access terminal in traffic with the CDMA 2000 1xEV-DO system, the hybrid access terminal comprising:
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a timer for measuring a switching time when the hybrid access terminal is switched from the 1xEV-DO mode to the 1X mode;
a searcher module for tracking and converting frequency so as to perform the switching of the hybrid access terminal between the 1X mode and the 1xEV-DO mode, and receiving overhead messages;
a finger module for demodulating the overhead messages received from the searcher module; and
a mobile station modem (MSM) chip alternately and periodically searching the 1xEV-DO system and the 1X system, creating a return control signal if the MSM chip receives a return start signal from the timer while searching the 1X system, and delivering the return control signal to the searcher module. - View Dependent Claims (23, 24, 25)
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Specification