Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1999-12-09
2003-12-16
Cangialosi, Salvatore (Department: 2661)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S465000
Reexamination Certificate
active
06665296
ABSTRACT:
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
FIELD OF THE INVENTION
The present invention relates to the field of communication systems. More particularly, this invention comprises methods and apparatus for providing many individual customers with symmetric access to a broad-band, wide-area network, especially where capable telecommunications infrastructure is non-existent or very expensive to install.
BACKGROUND OF THE INVENTION
In the past few years, a new information revolution has caused the demand for communications to skyrocket. The emergence of the Internet as a new distribution and business medium, coupled with the continuing improvements in computing speed and power, have strained the ability of conventional networks to meet this burgeoning demand.
The installed base of conventional copper wires present inherent limitations and constraints to providing enhanced levels of communications services. Although new compression and signal processing techniques have enabled telephone companies to offer faster speeds and greater bandwidth using new services such as ISDN, DSL and ADSL, the market demand for more capacity will soon outpace these recent innovations. The use of optical fiber and cable television networks for new modes of communication is increasing, but fibers and cables have their own drawbacks and are relatively expensive to install and to maintain. Several satellite systems, including Teledesic™, Iridium™ and Globalstar™, are planning to offer world-wide high-speed services, but most of these companies will not roll out their full panoply of services for several years.
Each of these technologies supplies part of a solution to the problem of offering an improved global network, but none of them have yet conquered the holy grail of the telecommunications industry, the “last mile” of service. The most expensive segment of furnishing service to a customer is usually the last mile of the connection to the customer's location.
Several attempts to solve the problem of distributing information to large numbers of subscribers have met with mixed results. A number of these attempts are summarized below.
U.S. Pat. No. 2,288,802 issued to John Hays Hammond in 1942 and entitled Signaling System discloses a radio transmission system which employs a carrier wave that is transmitted in two substantially independent channels. The channels are “made independent” by using polarizations which propagate at right angles to each other. The carrier waves may also be modulated “by the same signal frequency, but with a predetermined phase relationship between the two modulations.” See Hammond, Column 1, Lines 1-24.
U.S. Pat. No. 4,747,160, issued to Bernard Bossard on May 24, 1988 and entitled Low Power Multi-Function Cellular Television System describes a network of low power, substantially omni-directional cell node transmitters which communicate with a directional receiving antennas. Bossard's omni-directional transmitter imposes severe constraints on the ability of this system to provide diverse information services to many different customers.
One particular disadvantage of Bossard's system, which is due to its omni-directional signal, is the limitation of the system to compensate for rainfall in small portions of customer cells. Since the entire signal must be amplified at an omni-directional broadcast node, the system runs the risk of overpowering the signal to customers which are unaffected by the storm fronts. Bossard compensates for this constraint by limiting cell size.
Another severe limitation of the Bossard invention is the inability of the Bossard system to transmit to a single customer, or to transmit different signals to many different customers. The cell size in Bossard's system is also limited to the amount of power generated, which is dependent on the available (TWT) of about 100 watts. The base case for Bossard's system might be a quadratic cell for a “substantially” omni-directional system, in which a 100 watt TWT might be located in each of four quadrants of a broadcast cell, limiting the cell broadcast power to approximately 400 watts.
In 1977, Xerox Corporation initiated work on the Xerox Telecommunications Network (XTEN), a nationwide, high-speed, end-to-end, digital communications service. XTEN was designed to provide local data services using a combination of substantially omni-directional transmission from cell nodes and point-to-point return links from transceivers located at business premises. Local networks were to be connected by intercity satellite or terrestrial “backbone” facilities. See
Xerox Petition for Rulemaking
, filed with the Federal Communications Commission on Nov. 16, 1978. See also Xerox Comments on the DTS Notice of Proposed Rulemaking, filed with the Federal Communications Commission on Jan. 14, 1980.
Siemens Corporation received U.S. Pat. No. 1,586,260 from the Federal Republic of Germany in 1977. This patent, entitled A Radio Telecommunications System, discusses a system which connects stationary subscriber stations to a telecommunications network such as a public telephone network. A radio concentrator, assigned to a dial-operated exchange, is connected to the stationary subscribers via an omni-directional antenna. See Siemens '260, Column 1, Lines 9-13 and Lines 21-24.
Siemens was also awarded French Patent No. 1,024,523 entitled Réseau d'émetteurs d'ondes Ultra-courtes, which also pertains to transmission of radio and television programs. See Siemens '523, Resumé, Column 4.
In June of 1982, George Jacobs published a paper entitled
Low Power Television
in IEEE Spectrum. Jacobs explains the impact of the development of short-range, low-cost television systems.
FIG. 3
of his article reveals the components of a low-power television station designed to produce electromagnetic power of a kilowatt or less.
Donald Silverman offers an analysis of an integrated, end-to-end digital communications service which may be used to augment existing inter-city network facilities in his paper entitled
The Digital Termination System Solution for High Speed Local Distribution
. This paper was published in the January, 1983 edition of Microwave Journal.
The IEEE Spectrum published a paper in June, 1983 by George Cooper and Ray Nettleton entitled
Cellular Mobile Technology. The Great Multiplier
. This article discusses the advantages of a cellular mobile communications system, interference problems, narrowband modulation, digital transmission, space diversity techniques which reduce fading and spread-spectrum and frequency hopping methods.
In their paper entitled
Multiple Access Digital Microwave Radio System for Local Subscribers
, Nasatoshi Murakami et al. describe a radio communication system which provides point-to-multipoint digital transmission in a metropolitan area. See IEEE International Conference on Communications '83, June 1983, pp. b2.5.1.
In an article entitled
Digital Termination Systems
, Walter Urich and Ronald Bohm describe a common carrier service designed to provide flexible, low-cost digital communications within a community using a portion of the microwave spectrum. See Computerworld, Jun. 6, 1984, pages 35-38.
In U.S. Pat. No. 4,525,861 issued in 1985, Thomas Freeburg explains the details of his
Zoned Data Communications System for Communicating Message Signals between Portable Radios and a Host Computer
. This system serves a geographic area that is divided into a number of non-overlapping zones. Signals carrying alphanumeric information are conveyed among a general communications controller and a number of portable radios. See Freeburg, Abstract, Lines 1-9.
Douglas Morais describes a Radio Communication System Using Frequency Division Multiplexing for Transmission between a Master Station and a Plurality of Remote Stations in his U.S. Pat. No. 4,528,656, printed in 1985. Morais' point-to-multipoint radio communication system includes a master station and a number of remote stations which communicate using frequency division multiplexing.
Alfred Mack dis
Liron Moshe L.
Sturza Mark A.
Cangialosi Salvatore
Giaccherini Thomas N.
Social Fabric Corporation
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