发明名称 |
IMPROVED IN-CALL DTMF TRANSPORT FOR GEOSTATIONARY MOBILE SATELLITE COMMUNICATION SYSTEM |
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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申请公布号 |
WO0031984(A3) |
申请公布日期 |
2000.12.21 |
申请号 |
WO1999US27765 |
申请日期 |
1999.11.23 |
申请人 |
HUGHES ELECTRONICS CORPORATION |
发明人 |
RAVISHANKAR, CHANNASANDRA;ROOS, DAVID;NOERPEL, ANTHONY;JOSHI, CHANDRA;HOBZA, JAMES;DATTA, PRABIR;CHEN, YI |
分类号 |
H04M3/22;H04M3/533;H04Q1/45;H04Q7/20 |
主分类号 |
H04M3/22 |
代理机构 |
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主权项 |
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地址 |
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