International Business Machines Corporation

Bruce D Gobioff

Joseph A Alvarez, Iii

Lynn P West

Robert W Krug

John F Brennen

John Shabe

A method and apparatus are disclosed for conducting broadcast, multipoint, and conference communications in a TDMA network at various data rates while simultaneously conducting point-to-point communications at other data rates, either between local ports or between geographically remote ports during time intervals within a TDMA burst, which are not necessarily predefined. The disclosed apparatus appends a direct destination address to each point-to-point port communication for transmission over a communications link, to directly address the intended destination port. The disclosed invention appends an indirect destination address to each broadcast communication transmitted over the communications link. A broadcast memory is provided at the receiving end of the communications link, for storing correlated direct addresses which are accessed by the indirect destination addresses, to directly address a plurality of intended destination ports. In this manner, both point-to-point and broadcast-type communications can be carried out for a variety of data rates, during time intervals which are not predetermined within the TDMA burst, and with a high degree of connectivity.

Time domain multiple access broadcasting, multipoint, and conferencing

In a time division multiple access (TDMA) system, for 'multi-path' data communication via satellite repeater, the form of transmitted data is varied adaptively to maintain error-free transmission under varying noise conditions. Adjustments are made on a path selective and channel selective basis to protect only the most vulnerable data in specific transmission paths experiencing noise deterioration. Accordingly any multi-channel burst may contain channels of data in both protected and unprotected forms. A predetermined portion of each channel containing data in unprotected format is used explicitly to designate the destination of the accompanying data and implicitly to distinguish the data format as unprotected. In protected format data including error protective coding is transmitted in two contiguous channels along with information in the first channel explicitly distinguishing the protected format. This format-distinguishing information occupies the space allotted in the unprotected format for designating the data destination. The destination of protectively encoded data is explicitly designated in a separate predetermined space in the associated double-channel slot.

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Wheaton, MD, United States of America

Bruce D Gobioff