Bit compression multiplexing

• US 4,697,264 A
• Filed: 10/10/1985
• Issued: 09/29/1987
• Est. Priority Date: 05/19/1983
• Status: Expired due to Term

• Current Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Original Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Inventors: Galensky, Duane, Hammett, Warren G.
• Primary Examiner(s): Orsino, Jr., Joseph A.
• Application Number:
  US06/786,292
• Time in Patent Office: 719 Days
• Field of Search: 370/99, 370/110.1, 370/111
• US Class Current: 370/521
• CPC Class Codes: H04J 3/047 Distributors with transistors or integrated circuits
• CPC Class Codes: H04J 3/1682 Allocation of channels according to the instantaneous demands of the users, e.g. concentrated multiplexers, statistical multiplexers
• CPC Class Codes: H04J 3/1688 the demands of the users being taken into account after redundancy removal, e.g. by predictive coding, by variable sampling reducing bandwidth of signals in general H04B1/66; in PCM-systems H04B14/046; removal of redundancy in telegraph communication H03M7/30

Abstract

A bit compression multiplexer for a pair of time division multiplexed digital bit streams each one of which includes a plurality of PCM encoded signals deposited in separate and distinct channels and signaling bits multiplexed therewith. The encoded signals are bit compressed (22), and then multiplexed and grouped (25) into clusters. Each of the multiplexed compressed signals occupies a separate and distinct channel of a repetitive frame that includes a plurality of clusters and a corresponding number of additional channels, called delta channels, each one of which is associated with a given cluster and is proximate thereto. The signaling bits are extracted (21) from the pair of digital bit streams, reformatted (24) and then placed in predetermined bit positions of the delta channels. The signaling bits in a given delta channel are associated with the compressed signals of a cluster proximate thereto. The combination of a cluster and its related delta channel comprise a bundle. A framing bit pattern is developed (23) for each bundle and the framing bits are placed into a predetermined bit position of each of the delta channels.

Claims

1. A bit compression multiplexing system for a pair of time division multiplexed digital bit streams each of which includes a plurality of PCM encoded signals in separate and distinct channels of a repetitive frame and signaling bits multiplexed therewith comprising:

means (22) for bit-rate compressing the PCM encoded signals into differential PCM signals;

means (25) for multiplexing the compressed differential PCm signals and grouping the same into clusters, each of the clusters including predetermined number of compressed signal channels and each of the compressed differential PCM signals occupying a separate and distinct channel of a repetitive frame that includes a plurality of said clusters and a corresponding plurality of additional channels each one of which is associated with a given cluster and is proximate thereto, wherein a predetermined number of said repetitive frames forms a repetitive superframe;

means (21, 24,

     25) for extracting and reformatting the signaling bits of said time division multiplexed digital bit streams and placing the same in predetermined ones of said plurality of additional channels in the repetitive frames of said superframe, the signaling bits in a given additional channel being associated with the compressed differential PCM signals of a cluster proximate thereto; and

means (23,

     24) for developing a framing bit pattern for each of said plurality of clusters and for inserting the bits of the same into a predetermined bit position of the additional channel associated with an proximate to each of said clusters in the reptitive frames of said superframe.

2. A bit compression multiplexing system as defined in claim 1 wherein a frame of compressed signals is of the same duration as a frame of said pair of digital bit streams.

3. A bit compression multiplexing system as defined in claim 2 wherein each of the pair of multiplexed digital bit streams carries sixteen state signaling.

4. A bit compression multiplexing system as defined in claim 2 wherein a predetermined bit position of each of said dditional channels is reserved to provide low bit rate data links.

5. A bit compression multiplexing system as defined in claim 2 including means (47) coupled to the multiplexing means for periodically inserting an alarm bit in a given additional channel to indicate a bundle-alarm condition.

6. A bit compression multiplexing system as defined in claim 2 wherein the digital bit streams are DS1 signals.

7. A bit compression multiplexing method for a pair of time division multiplexed digital bit streams each of which includes a plurality of PCM encoded signals in separate and distinct channels of a repetitive frame and signaling bits multiplexed therewith comprising the steps of:

bit-rate compressing the encoded PCM signals into differential PCM signals;

multiplexing the compressed differential PCM signals and grouping the same into clusters, each of the clusters including a predetermined number of multiplexed compressed signal channels and each of the compressed differential PCM signals occupying a separate and distinct channel of a repetitive frame that includes a plurality of said clusters and a corresponding plurality of additional channels each one of which is associated with a given cluster and is proximate thereto, wherein a predetermined number of said repetitive frames forms a repetitive superframe;

extracting the signaling bits from the pair of time division multiplexed digital bit streams;

reformatting the extracted signaling bits and placing the same in predetermined bit positions of said additional channels in the repetitive frames of said superframe, the signaling bits in a given additional channel being associated with the compressed differential PCM signals of a cluster proximate thereto; and

developing a framing bit pattern for each of said plurality of clusters and inserting the bits of the same into a predetermined bit position of the additional channel associated with and proximate to each of said clusters in the repetitive frames of said superframe.