Trellis coder and method for trellis coding in a device or a method for digital data transmission

摘要

A method and apparatus for carrying out synchronous co-division multiple access (SCDMA) communication of multiple channels of digital data over a shared transmission media (1162). The system includes modems at remote units (1164) and a central unit (1160) to receive time division multiplexed digital data arranged into timeslots or channels and uses orthogonal codes to encode each channel of multiple data and spread the energy of each channel data over a frame of data transmitted in a code domain. Frames are synchronized as between remote (1164) and central units (1160) using a ranging scheme which is also useful in any other system transmitting data by frames in a distributed system where synchronizing the frames as between all units regardless of differences in propagation delays is necessary. Each frame in the SCDMA modulation scheme includes a gap or guardband containing no other data. IMAGE