Communication method and apparatus using data compression

Details Communication method and apparatus using data compression Communication method and apparatus using data compression

1998-02-27

2001-03-20

Tse, Young T. (Department: 2634)

Pulse or digital communications

Bandwidth reduction or expansion

C375S222000, C379S093050, C455S072000

Reexamination Certificate

active

06205173

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a data communication method and apparatus and in particular to a data interface for connection between first and second communications sub-links.
BACKGROUND ART
One example of a communications link for use in connection with data terminal equipment (DTE) is an asynchronous data service proposed for the INMARSAT-B (TM) or INMARSAT-M (TM) satellite communication systems, as described for example in chapters 12 and 14 of “Satellite Communications: Principles and Applications” by Calcutt and Tetley, First Edition, published by Edward Arnold.
The overall layout of the satellite communication system, when used for data communications, is shown in
FIG. 1. A
mobile DTE 2 is connected via an RS232 interface to a mobile modem interface unit (MIU) 4. The mobile MIU 4 simulates a modem, so that off-the-shelf communication software may be used in the mobile DTE 2. The MIU 4 provides an interface to a mobile earth station (MES) 6 which allows communication via a satellite 8 to a fixed or land earth station (LES) 10. The LES 10 is connected to a fixed MIU 12 which interfaces the satellite link to a public switched telephone network (PSTN) 14. A fixed DTE 18 is connected to the PSTN 14 through a modem 16 of standard type.
Under good conditions, the PSTN 14 should be capable of supporting bit rates as high as 28,800 bits per second or more. However, the INMARSAT-M satellite link supports a maximum data rate of 2400 bits per second, while the INMARSAT-B system supports a maximum of 9600 bits per second. If an acceptable bit error rate for data communications is to be provided over the satellite links, the data transfer rate must be limited, and so the PSTN link is limited to the data rate available over the satellite link.
The document EP-A-0566407 discloses an interface between a local area network and an RF segment of a terrestrial cellular system, in which compressed voice traffic from a mobile terminal is expanded for transmission to a PSTN, but remains in compressed form if the voice traffic is intended for reception by another mobile terminal, to avoid double coding of speech. However, such an interface does not allow a user to communicate using either compressed or uncompressed data over the same network.
STATEMENT OF INVENTION
According to the present invention, there is provided a data communications interface for connection between a first communications link and a second, radio frequency communications link, which is capable of sending compressed data to and receiving compressed data from either of the communications links. In this way, the information rate through the second communications link may be increased, and when uncompressed data is sent over the first communication link, the first link can operate at a higher data rate than the second communications link. Preferably, the interface apparatus is able to send and receive compressed data over the second communications link, while being able to send data to and receive data from the first communications link in either compressed or uncompressed form. In the former case, the interface is operable to decompress data from one link and to recompress the data for transmission over the other link, so that compression protocols can be operated independently over each link.


REFERENCES:
patent: 5307413 (1994-04-01), Denzer
patent: 5337319 (1994-08-01), Furukawa et al.
patent: 5404394 (1995-04-01), Dimolitsas et al.
patent: 5850602 (1998-12-01), Tisdale et al.
patent: 5968149 (1999-10-01), Jaquette et al.
patent: 5974043 (1999-10-01), Solomon
patent: C 44 09 128 (1995-01-01), None
patent: 0 393 646 (1990-10-01), None
patent: 0 650 270 (1995-04-01), None
patent: WO A 91 15087 (1991-10-01), None
patent: WO A 94 10809 (1994-05-01), None

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