US 5,065,396 AGranted

Inverse multiplexer and demultiplexer techniques

AssigneeAT&T Bell Laboratories

InventorsJames J. Castellano, John H. Leshchuk, Michael L. Steinberger

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Abstract

An Inverse Multiplexer is disclosed which first demultiplexes a first data rate input signal into a plurality of second lower data rate subsectional signals, where each subsectional signal is provided with a periodic synchronization marker and includes a data rate which is less than the channel data rate used to transmit that subsectional signal to a remote terminal. Programmable Multiplexers (PMUXs) then operate to each take one or more subsectional signals that are (1) clock synchronized to a PMUX clock, and (2) a rational fraction of the channel data rate, and map contiguously assigned time slots in a capacity domain frame for each subsectional signal to time slots of a time domain frame format using a 2-step or 3-step digit reverse technique. The resultant time domain format has the input subsectional capacity domain time slots substantially uniformly distributed over the time domain frame. At the receiving end, an Inverse Demultiplexer performs the reverse operation to recover the original first data rate input signal.

A method of transmitting a first data rate input signal to a remote terminal over transmission channels including a lower second data rate, the method comprising the steps of:

(a) demultiplexing the first data rate input signal into a plurality of subsectional output signals, each subsectional output signal comprising a data rate which is lower than the second data rate;
(b) inserting a marker signal at a predetermined timing relationship into each of the plurality of subsectional output signals at predetermined intervals;
(c) receiving at separate inputs of each of one or more rate adaptor means, subsectional output signals from step (b) that in combination for each rate adaptor means does not total more than the capacity of the second data rate, and inserting those subsectional output signals into a separate output signal at the second data rate;
and
(d) transmitting two or more second data rate signals from step (c) two or more second data rate transmission channels to a remote one or more receivers for recovery of the first data input signal;
wherein in performing step (c) performing the substeps of:
(c1) assigning each subsectional output signal associated with a rate adaptor means to or one or more predetermined contiguous addresses of a capacity domain frame dependent on the data of the received subsectional output signal, where the capacity domain frame includes a predetermined number of assignable addresses;
(c2) in each rate adaptor means, converting each of the contiguous addresses of the capacity domain frame for each of the received subsectional output signals from step (b) to non-contiguous addresses in a time domain frame so that the non-contiguous addresses are substantially uniformly distributed over the time domain frame;
and
in performing step (d) transmitting sections of one of the subsectional output signals during each address of the time domain frame sequence, as determined in step (c), via one of the second data rate transmission channels to a remote one or more receivers for recovery of the first data rate input signal.

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Abstract

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