发明授权
US06650895B1 In-call DTMF transport for geostationary mobile satellite communication system
有权
用于对地静止移动卫星通信系统的通话DTMF传输
- 专利标题: In-call DTMF transport for geostationary mobile satellite communication system
- 专利标题(中): 用于对地静止移动卫星通信系统的通话DTMF传输
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申请号: US09447696申请日: 1999-11-23
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公开(公告)号: US06650895B1公开(公告)日: 2003-11-18
- 发明人: Channasandra Ravishankar , David Roos , Anthony Noerpel , Chandra Joshi , James Hobza , Prabir Datta , Yi Chen
- 申请人: Channasandra Ravishankar , David Roos , Anthony Noerpel , Chandra Joshi , James Hobza , Prabir Datta , Yi Chen
- 主分类号: H04Q720
- IPC分类号: H04Q720
摘要:
A system and a methodology to improve the end-user quality of service both in terms of response time and reliability for the transport of in-call DTMF signals in wireless systems, particularly in geostationary mobile satellite systems. The methodology encompasses several techniques to provide acceptable end-to-end quality of service for DTMF. A technique is applicable for transport of DTMF in the wireless subscriber to network direction, where DTMF digits are carried in the form of an out-band message. The central part of the technique is to allow multiple key presses in the same message, thereby increasing efficiency and throughput in long-delay environment. Another technique utilizes the vocoder's functionality to carry DTMF in-band, thereby reducing system complexity. The scheme makes the use of an integrated DTMF detector which can classify a given frame of signal into several classes so that the DTMF encoded packet can carry a unique pattern across the air-interface to the voice decoder at AT, which is capable of identifying the pattern. Another technique pertains to the use of a message based DTMF transport between two-ATs on a separate logical channel with a unique Service Access point Identifier (SAPI) providing guaranteed service for DTMF transport in an AT-AT call.
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