EP0222544A2
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Method of multiplexing digital signals
Assignee: Nortel Networks Ltd
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Filing: 1986-10-24
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Granted: —
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Expires: 2006-10-24
Abstract
Abstract A multiplexed bit stream consists of interleaved words all of the same number of bits, the words corresponding to respective channels one of which is a synchronizing channel. A predetermined one of the bits of the words is used to identify the synchronizing channel, and may be used in the other, information, channels to carry service-related overhead and signalling information. The bit rate of the multiplexed bit stream is a harmonic of the bit rate of the individual channels. Such but streams can be further multiplexed together in a word-interleaved harmonic manner, whereby a harmonic structure of signals at different levels of multiplexing is built up.
Inventors
- 👤 Alan Frank Graves
- 👤 Paul Ashley Littlewood
- 👤 Johannes Siegfried Weiss
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 06:02
CPC Classifications
H; H04; H04Q; H04Q11/00; H04Q11/04; H04Q11/08; H04J; H04J3/00; H04J3/02; H04J3/06; H04J3/0602; H04J3/08; H04J3/12; H04J3/16; H04J3/1605; H04J3/1611
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
105 words
A method of multiplexing digital signals comprising the steps of: providing t.d.m. frames each consisting of m.n time slots each for one bit, where m and n are plural integers, said time slots comprising n consecutive time slots for each of m channels; and, in each frame: in a predetermined one of the n time slots for one of the m channels, providing a bit indicating that the channel is a frame synchronizing channel, whereby this frame synchronizing channel is distinguishable from information channels constituted by the other m-1 channels; and providing digital signals in the outer n-1 time slots of the m-1 information channels.
Claim 2
Independent Claim
105 words
A method of multiplexing digital signals comprising the steps of: providing t.d.m. frames each consisting of m.n time slots each for one bit, where m and n are plural integers, said time slots comprising n consecutive time slots for each of m channels; and, in each frame: in a predetermined one of the n time slots for one of the m channels, providing a bit indicating that the channel is a frame synchronizing channel, whereby this frame synchronizing channel is distinguishable from information channels constituted by the other m-1 channels; and providing digital signals in the outer n-1 time slots of the m-1 information channels.
Claim 3
Dependent Claim
33 words
A method as claimed in claim 1 wherein said bit provided in each frame in the predetermined one of the n time slots of the frame synchronizing channel has a predetermined binary value.
Claim 4
Dependent Claim
40 words
A method as claimed in claim 2 and including the step of providing in each frame in the predetermined one of the n time slots of each information channel a bit having a value different from said predetermined binary value.
Claim 5
Dependent Claim
33 words
A method as claimed in claim 3 and including the step of providing in each frame a signalling information bit in a further one of the n time slots of each information channel.
Claim 6
Dependent Claim
42 words
A method as claimed in claim 2 and including the step of providing, in successive frames in the predetermined one of the n time slots of each information channel, bits of both binary values constituting overhead information for the respective information channel.
Claim 7
Dependent Claim
29 words
A method as claimed in claim 5 wherein the overhead information for each information channel provides one bit every six frames for signalling information relating to the information channel.
Claim 8
Dependent Claim
44 words
A method as claimed in claim 5 or 6 wherein the overhead information for each information channel comprises bits in overhead information frames, each overhead information frame having a period which is an integral multiple of the period of six of said t.d.m. frames.
Claim 9
Independent Claim
33 words
A method as claimed in any of claims 1 to 7 and further comprising the step of providing information in each frame in the other n-1 time slots of the frame synchronizing channel.
Claim 10
Dependent Claim
29 words
A method as claimed in claim 8 wherein the information provided in each frame in the other n-1 time slots of the frame synchronizing channel comprises signalling frame information.
Claim 11
Independent Claim
21 words
A method as claimed in any of claims 1 to 9 wherein the t.d.m. frames each have a period of 125us.
Claim 12
Independent Claim
13 words
A method as claimed in any of claims 1 to 10 wherein m=25.
Claim 13
Independent Claim
13 words
A method as claimed in any of claims 1 to 11 wherein n>8.
Claim 14
Dependent Claim
9 words
A method as claimed in claim 12 wherein n=9.
Claim 15
Dependent Claim
9 words
A method as claimed in claim 12 wherein n=10.
Claim 16
Dependent Claim
40 words
A method as claimed in claim 12 or 14 and including the step of providing a parity bit for each information channel in each frame in a predetermined one of the other n-1 time slots of the respective information channel.
Claim 17
Independent Claim
39 words
A method as claimed in any of claims 12 to 15 wherein in each frame 8 bits of 64kbps channel are provided in 8 of said other n-1 time slots of at least one of the m-1 information channels.
Claim 18
Independent Claim
116 words
A method of multiplexing digital signals comprising the steps of: providing p virtual tributaries each comprising t.d.m. frames of information multiplexed in accordance with the method of any of claims 1 to 16, where p is plural integer, all of the virtual tributaries having the same t.d.m. frame period and the same number m.n of time slots for m words each of n consecutive bits; providing a predetermined synchronizing word as a predetermined one of the m words of a predetermined one of the virtual tributaries constituting a synchronizing information tributary; and multiplexing the p virtual tributaries together, one word from each virtual tributary cyclically in turn, to form a multiplexed superframe of word-interleaved virtual tributaries.
Claim 19
Dependent Claim
20 words
A method as claimed in claim 17 wherein a plurality of synchronizing words are provided in the synchronizing information tributary.
Claim 20
Dependent Claim
41 words
A method as claimed in claim 18 wherein the synchronizing information tributary comprises a number of different synchronizing words which is an integral factor of m, the synchronizing words being distributed periodically among the m words of the synchronizing information tributary.
Claim 21
Dependent Claim
18 words
A method as claimed in claim 18 or 19 wherein the synchronizing information tributary comprises five synchronizing words.
Claim 22
Independent Claim
13 words
A method as claimed in any of claims 17 to 20 wherein p=32.
Claim 23
Independent Claim
70 words
A method of multiplexing digital signals comprising the steps of: providing a plurality of multiplexed superframes of word-interleaved virtual tributaries multiplexed in accordance with the method of any of claims 17 to 21; modifying the predetermined synchronizing word of a predetermined one of the multiplexed superframes whereby it is distinguishable from the other synchronizing words; and multiplexing the multiplexed superframes together, one word from each multiplexed superframe cyclically in turn.
Claim 24
Independent Claim
98 words
A method of multiplexing comprising the steps of: multiplexing in a t.d.m. frame an n-bit word of each of a frame synchronizing channel and m-1 digital signal channels to form a tributary channel having m.n bits in each t.d.m. frame period; and multiplexing in a t.d.m. subframe an n-bit word of each of a tributary synchronizing channel, also having m.n bits in each t.d.m. frame period, and p-1 tributary channels to produce a multiplexed signal having p.n bits in each t.d.m. subframe and m subframes in each t.d.m frame period; where n, m, and p are plural integers.
Claim 25
Independent Claim
98 words
A method of multiplexing comprising the steps of: multiplexing in a t.d.m. frame an n-bit word of each of a frame synchronizing channel and m-1 digital signal channels to form a tributary channel having m.n bits in each t.d.m. frame period; and multiplexing in a t.d.m. subframe an n-bit word of each of a tributary synchronizing channel, also having m.n bits in each t.d.m. frame period, and p-1 tributary channels to produce a multiplexed signal having p.n bits in each t.d.m. subframe and m subframes in each t.d.m frame period; where n, m, and p are plural integers.
Claim 26
Dependent Claim
57 words
A method of multiplexing as claimed in claim 23 and further comprising the step of: multiplexing in a t.d.m. sub-subframe an n-bit word of each of q of said multiplexed signals to produce a further multiplexed signal having q.n bits in each t.d.m. sub-subframe and p sub-subframes in each t.d.m. subframe; where q is a plural integer.
Claim 27
Dependent Claim
17 words
A method as claimed in claim 23 or 24 wherein the t.d.m. frame period is 125 microseconds.
References Cited (Backward Citations)
JPS54146517A
Cited
EP0053230A1
Cited
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