Multiplex communications – Communication techniques for information carried in plural... – Combining or distributing information via time channels
Reexamination Certificate
1998-02-27
2001-06-05
Olms, Douglas W. (Department: 2732)
Multiplex communications
Communication techniques for information carried in plural...
Combining or distributing information via time channels
C370S376000
Reexamination Certificate
active
06243400
ABSTRACT:
RELATED APPLICATION
This application is related to an application entitled “Dynamic Assignment of Subrate Voice Channels in Telecommunication Networks” being filed concurrently by the inventors of this application and being assigned to the same assignee.
TECHNICAL FIELD
This invention relates to methods and apparatus for switching digital voice signals in telecommunication networks.
PROBLEM
Today, a very large fraction of voice telecommunications traffic is transmitted in digital form. Most of this traffic is transmitted as a series of pulse code modulation (PCM) signals wherein eight thousand samples per second are transmitted each as an eight bit quantity. The 64 kilobit per second signal faithfully reproduces voice signals in the telephone band (i.e., between 200 and 3300 Hertz). It is well known that 64 kilobits are not required to faithfully reproduce voice signals in the telephone band. Recently, many low cost coder/decoders (Codecs) have been found which will transmit the faithful reproduction of voice signals at subrates of 32 kilobits per second, 16 kilobits per second, 8 kilobits per second and even lower rates, thus permitting a full rate (64 kilobits per second) channel to convey multiple voice signals. As a result, the opportunity exists to use present time slot interchange (TSI) switches designed to switch 64 Kb signals, for switching many more voice signals than is possible with the exclusive use of 64 kilobits per second coding and switching. However, the prior art does not teach any good way of mixing different voice signal rates in economical switching systems without requiring a radical redesign of these systems and a very costly replacement effort. A problem of the prior art, therefore, is that there is no economical way of introducing different rates (subrates) of voice transmission into the digital switches designed for switching full rate (64 kilobit per second) signals.
SOLUTION
The above problem is solved and an advance is made over the prior art in accordance with our invention wherein sub-rate voice signals are generated and bundled into full rate signals (e.g., 64 kilobit signals) prior to being switched in a digital switch such as a TSI switching network (switch); the bundling is performed in such a way as to minimize intermediate sub-rate switching by assembling sub-rate signals for a common destination (port).
In accordance with one preferred embodiment of Applicants' invention, a line or trunk unit, for serving lines or trunks whose service profile indicates that they may use compressed (subrate) signals, comprising a plurality of 64K Codecs is connected to a first unit which compresses selected 64K signals and bundles them into a smaller number of 64K outputs. These bundled signals are then switched, using existing TSI switching fabrics, transmitted to a destination switch module, and unbundled in a second unit which decompresses bundled 64K signals into single voice 64K signals for transmission to a destination line or an intermediate trunk.
REFERENCES:
patent: 4965787 (1990-10-01), Almond et al.
patent: 5287350 (1994-02-01), Ito et al.
patent: 5784369 (1998-07-01), Romiti et al.
patent: 6044082 (2000-03-01), Nygard et al.
patent: 6047007 (2000-04-01), Munday et al.
patent: 6052391 (2000-04-01), Deutsch et al.
Deutsch Douglas Anthony
Smith David B.
Lucent Technologies - Inc.
Olms Douglas W.
Ulrich Werner
Vanderpuye Ken
LandOfFree
Subrate voice switching over switching and telecommunication... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Subrate voice switching over switching and telecommunication..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Subrate voice switching over switching and telecommunication... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2469614