EP0257901A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Switching techniques for FDM communication systems
Assignee: AT&T Inc
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Filing: 1987-08-10
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Granted: —
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Expires: 2007-08-10
Abstract
Abstract The present invention relates to a switching technique for packet Frequency Division Multiplexed (FDM) communication systems. In the present system, each of N system users is assigned (a) either a separate fixed one of N transmit frequency channels or a selected free one of L transmit frequency channel for communications to a head-end FDM channel switching means (10), and (b) a fixed assigned separate one of N receive channels for communications from the head-end FDM channels switching means. At the FDM channel switching means, all FDM channel signals received from the system users are directed into separate paths (21) through the switching means. The signals in each path are demodulated (23) to baseband, and a destination address in each packet is detected (28) to determine where each packet is to be sent. Each path in the switching means is hard-wired therethrough to an associated transmitting oscillator (29) which is frequency tuned, by means of the detected destination address, to the unique frequency channel of the user or the external network which is the desired destination of the packet. Thus, switching of a packet signal is accomplished without ever connecting or disconnecting wire lines.
Inventors
- 👤 Thomas Edward Darcie
- 👤 Michael James Gans
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 07:49
CPC Classifications
H; H04; H04J; H04J1/00; H04J1/02; H04J1/12; H04J1/04; H04J1/05; H04L; H04L12/00; H04L12/28; H04L12/2801
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
266 words
An arrangement for Frequency Division Multiplexed (FDM) switching of information signals in a communication system comprising N users CHARACTERISED IN THAT each user is assigned to receive information signals destined for that user over a separate one of N receive channels and to transmit information signals over a separate one of L transmit channels, where L ≦ N, the switching arrangement comprising: means for receiving up to a plurality of L concurrent multiplexed information signals from a corresponding plurality of up to L active system users and for directing each of the up to L concurrently received information signals to a separate one of L output terminals, each information signal including a destination user's address which is different for each system user; a plurality of L paths for propagating up to L concurrent information signals through the switching arrangement, each path being connected to a separate one of the output terminals of the receiving and directing means and including; means responsive to the signal information propagating on each of the plurality of L paths for (a) detecting the destination user's address included in each information signal on each path and (b) generating a separate control signal representative of each detected destination user's address, and transmitting means responsive to the control signals from the detecting and generating means for converting the information signal propagating on each of the plurality of L paths to the FDM receive channel assigned to the destined user as indicated by the destination user's address detected in the information signal on that path for subsequent transmission of the signal to the destined user.
Claim 2
Dependent Claim
266 words
An arrangement for Frequency Division Multiplexed (FDM) switching of information signals in a communication system comprising N users CHARACTERISED IN THAT each user is assigned to receive information signals destined for that user over a separate one of N receive channels and to transmit information signals over a separate one of L transmit channels, where L ≦ N, the switching arrangement comprising: means for receiving up to a plurality of L concurrent multiplexed information signals from a corresponding plurality of up to L active system users and for directing each of the up to L concurrently received information signals to a separate one of L output terminals, each information signal including a destination user's address which is different for each system user; a plurality of L paths for propagating up to L concurrent information signals through the switching arrangement, each path being connected to a separate one of the output terminals of the receiving and directing means and including; means responsive to the signal information propagating on each of the plurality of L paths for (a) detecting the destination user's address included in each information signal on each path and (b) generating a separate control signal representative of each detected destination user's address, and transmitting means responsive to the control signals from the detecting and generating means for converting the information signal propagating on each of the plurality of L paths to the FDM receive channel assigned to the destined user as indicated by the destination user's address detected in the information signal on that path for subsequent transmission of the signal to the destined user.
Claim 3
Dependent Claim
138 words
An FDM switching arrangement according to claim 1 CHARACTERIZED IN THAT the switching arrangement further comprises: a network monitor including means for receiving the information signals from each of the plurality of L paths, and for generating a separate information signal for a selected path, concurrent with the received information signal, which includes information to be inserted into certain portions of the information signal propagating in the selected path preceded and succeeded by a predetermined control code which is unique for the selected path; and each path further includes inserting means disposed before the transmitting means, the inserting means being responsive to the reception of the unique control code identifying the selected path, which precedes and succeeds the information to be inserted into an information signal propagating in the selected path, for inserting the information into that signal.
Claim 4
Dependent Claim
137 words
An FDM switching arrangement according to claim 2 CHARACTERIZED IN THAT the inserting means comprises: a plurality of L self-routing switches (SRS), where each SRS is disposed in a separate one of the plurality of L paths and comprises a first input connected to receive the information signal on the associated path, a second input connected to receive the information signals generated by the network monitor, and an output connected to both the transmitting means and the detecting and generating means, each SRS functioning to pass each information signal received at the first input and to overwrite any portion of the received information signal from the first input with the information disposed between the preceding and succeeding control code received at the second input when the control code corresponds to the unique code for the associated path.
Claim 5
Dependent Claim
184 words
An FDM switching arrangement according to claim 3 CHARACTERIZED IN THAT each self-routing switch (SRS) comprises: a first code switching means for detecting a first unique preceding and succeeding control code associated with each of the plurality of L paths disposed in a preamble section of each information signal received from the network monitor at the second input, and for inserting control information received at the second input, between the first unique preceding and succeeding control code, in place of the corresponding preamble information section received at the first input when the first control code corresponds to the unique first control code for the associated path; and a second code switching means for detecting a second unique preceding and succeeding control code associated with each of the plurality of L paths, which code is disposed adjacent the front and rear, respectively, of an overall information signal, for inserting the information signal from the network monitor in place of the packet of information signal received on the associated path when the second control code corresponds to the unique second control code for the associated path.
Claim 6
Dependent Claim
90 words
An FDM switching arrangement according to claim 4 CHARACTERIZED IN THAT the network monitor is further capable of (a) detecting if the destination user's address in each received information signal is the address of an external network connection, and the routing such information signal to the external network, and (b) routing information signals received from the external network onto the proper one of the plurality of L paths by adding the second unique control code adjacent the front and rear of the information signal before transmission to the inserting means.
Claim 7
Dependent Claim
90 words
An FDM switching arrangement according to claim 3 CHARACTERIZED IN THAT the information signal is an analog signal including control codes which are FDM tones, each self-routing switch comprising: signal introduction means including filtering means for passing only a unique control signal tone assigned to the associated one of the plurality of L paths; and code switching means responsive to the unique control signal tone from the filtering means for inserting an information signal received from the network monitor in place of the information signal received from the associated path.
Claim 8
Dependent Claim
59 words
An FDM switching arrangement according to claim 6 CHARACTERIZED IN THAT the self-routing switch further comprises: second signal introduction means including filtering means for passing only selected FDM control signal tones received from the network monitor, and an adder for adding the FDM control tones passed by the filtering means to an information signal received on the associated path.
Claim 9
Dependent Claim
221 words
An arrangement for Frequency Division Multiplexed (FDM) switching of information signals in a switched communication system comprising N users wherein each user receives signals from the switching arrangement destined for that user over a separate link and transmits information signals over a separate link to the switching arrangement, CHARACTERIZED IN THAT the switching arrangement comprises: a plurality of N paths, each path being arranged for receiving information signals from a separate of one the N links from the N users, each received information signal including a destination user's address which address is different for each system user; means responsive to the information signals on the plurality of N paths for (a) detecting the destination user's address included in each information signal on each of the paths, and (b) generating control signals representative of each detected destination user's address including in an information signal; and transmitting means responsive to the control signals from the detecting and generating means for converting each of the information signals received in the plurality of N paths to the FDM channel assigned to the user as indicated by the detected destination user's address in each of the information signals; and means for directing each of the converted information signals from the transmitting means onto the appropriate link associated with the destined user for transmission to that user.
Claim 10
Dependent Claim
221 words
An arrangement for Frequency Division Multiplexed (FDM) switching of information signals in a switched communication system comprising N users wherein each user receives signals from the switching arrangement destined for that user over a separate link and transmits information signals over a separate link to the switching arrangement, CHARACTERIZED IN THAT the switching arrangement comprises: a plurality of N paths, each path being arranged for receiving information signals from a separate of one the N links from the N users, each received information signal including a destination user's address which address is different for each system user; means responsive to the information signals on the plurality of N paths for (a) detecting the destination user's address included in each information signal on each of the paths, and (b) generating control signals representative of each detected destination user's address including in an information signal; and transmitting means responsive to the control signals from the detecting and generating means for converting each of the information signals received in the plurality of N paths to the FDM channel assigned to the user as indicated by the detected destination user's address in each of the information signals; and means for directing each of the converted information signals from the transmitting means onto the appropriate link associated with the destined user for transmission to that user.
Claim 11
Dependent Claim
142 words
An FDM switching arrangement according to claim 8 CHARACTERIZED IN THAT the switching arrangement further comprises: a network monitor including means for receiving the information signals from each of the plurality of N paths, and for generating a separate information signal for a selected path, concurrent with the received information signal, which includes information to be inserted into certain portions of the information signal propagating in the selected path, which information to be inserted is preceded and succeeded by a predetermined control code which is unique for the selected path; and each path further includes inserting means disposed before the transmitting means which is responsive to the reception of the unique control code identifying the selected path which precedes and succeeds the information to be inserted into an information signal propagating in the selected path for inserting the information into that signal.
References Cited (Backward Citations)
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