Multiplex communications – Fault recovery
Reexamination Certificate
1999-02-16
2001-10-23
Nguyen, Chau (Department: 2663)
Multiplex communications
Fault recovery
C455S505000
Reexamination Certificate
active
06307833
ABSTRACT:
BACKGROUND
The present invention relates generally to data distribution systems and methods, and more particularly, to an improved rain fade mitigation method and data distribution system that distributes data to personal computers.
The assignee of the present invention has developed a satellite-based data distribution system that is used to distribute data from content providers to client personal computers by way of a satellite. This system must reliably operate in the presence of rain.
One currently deployed data broadcasting system, known as the DirecPC™ system developed by Hughes Network Systems, for example, is believed to provide for rain fade mitigation. However, the specifics of the rain fade mitigation is not known. However, such rain fade mitigation is not as critical when transmitting video data. This is because in most cases, the loss of data typically does not result in a complete interruption in transmission. If some data is lost during transmission, the video image may be deteriorated, but the eyes and brain integrate what is displayed making the data loss relatively unnoticeable.
It would be an improvement to have a rain fade mitigation method and one way data distribution system that operates in a rain fade environment. It would also be an improvement to have a rain fade mitigation method and one way satellite-based data distribution system that distributes data to personal computers in a rain fade environment.
SUMMARY OF THE INVENTION
The present invention provides for a rain fade mitigation method and data distribution system, such as an RF or satellite-based data distribution system, that provides improved performance when the system operates in a rain fade environment. The present invention may be used with any microwave RF transmission system in which rain events degrade or attenuate the communications signal. Typical systems include satellite-based communications, and the like.
In a first embodiment, the system includes a transmitting processor that processes data packets comprising data to be transmitted. A data distribution system is used to transmit the data packets to one or more receivers located at remote locations. The data distribution system is used to transmit the data a first time. The data is then transmitted a second time after a time delay that is nominally equal to the duration of an average rain event. This time is on the order of 20-30 minutes. The receivers receive the data packets and recover the originally transmitted data.
In a second embodiment, the transmitting processor also comprises forward error correction processing software that adds forward error correction bits to data packets containing the data to be transmitted. The data distribution system is used to transmit the data packets to one or more receivers located at remote locations. The packets are transmitted two or more times with a time delay between transmissions that is nominally equal to the duration of an average rain event. The receivers receive the transmitted packets, and also comprise forward error correction software that processes the received data packets to reconstruct the original data. The number of forward error correction bits added to each packet is configurable, and is typically up to about fifty percent of the number of bits in the data packet.
In a third embodiment, the data packets include forward error correction bits and are transmitted one time at a relatively slow transmission rate. The data transmission rate is chosen so that the time required to transmit the data to the receiver is greater than or equal to the time necessary to transmit the data plus the amount of time equal to an average rain fade event (20-30 minutes).
The approaches implement by the present invention provide for more efficient overall data transfer and the ability to transfer large data files more efficiently than previous systems. The use of additional forward error correction bits (overhead) in the data packets transmitted to the client personal computers also allows the system to have a reduced bandwidth and reduced data transmission rate.
The present invention may add up to fifty percent additional overhead to the data packets. This allows the loss of fifty percent of the data while still allowing the data to be recovered at the client personal computers. This technique ensures reception of the transmitted data in a rain fade environment.
REFERENCES:
patent: 3842352 (1974-10-01), Cote
patent: 4099121 (1978-07-01), Fang
patent: 4298984 (1981-11-01), Baker
patent: 5745532 (1998-04-01), Campana, Jr.
patent: 5822310 (1998-10-01), Chennakeshu et al.
patent: 5850419 (1998-12-01), Todoroki et al.
patent: 5883581 (1999-03-01), Dorenbosch et al.
patent: 6028853 (2000-02-01), Haartsen
Barker Keith R.
Rafter Mark T.
Float Kenneth W.
Loral CyberStar, Inc.
Nguyen Chau
Trinh D.
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