Optical/radio local access network

• US 7,565,081 B1
• Filed: 08/22/2007
• Issued: 07/21/2009
• Est. Priority Date: 08/17/2000
• Status: Expired due to Fees

• Current Assignee: AT&T Intellectual Property II LP (AT&T, Inc.)
• Original Assignee: AT&T Intellectual Property II LP (AT&T, Inc.)
• Inventors: Lin, Lih-Yuan, Dodley, Jeevan Prakash, Miller, Robert R., Britz, David M.
• Primary Examiner(s): Leung; Christina Y
• Application Number:
  US11/894,928
• Time in Patent Office: 699 Days
• Field of Search: 398/115, 398/116, 398/117, 398/49, 398/55, 398/56, 398/70, 398/71, 398/72, 398/126
• US Class Current: 398/70
• CPC Class Codes: H04B 10/0795 Performance monitoring; Measurement of transmission parameters
• CPC Class Codes: H04B 10/11 Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
• CPC Class Codes: H04B 10/1123 Bidirectional transmission
• CPC Class Codes: H04B 10/1125 using a single common optical path
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04Q 11/0067 Provisions for optical access or distribution networks, e.g. Gigabit Ethernet Passive Optical Network (GE-PON), ATM-based Passive Optical Network (A-PON), PON-Ring
• CPC Class Codes: H04Q 2011/0026 using free space propagation (e.g. lenses, mirrors)
• CPC Class Codes: H04Q 2011/0081 Fault tolerance; Redundancy; Recovery; Reconfigurability

Abstract

A communication system includes a plurality of nodes and a plurality of point-to-point links that interconnect the plurality of nodes into a network. Each node includes an optical switch to controllably route a plurality of in-ports of the optical switch into a plurality of out-ports of the optical switch. Each point-to-point link includes a free space optical channel. A first free space optical channel couples to a first node through a receive path and through a transmit path. The receive path couples to a respective in-port of the optical switch of the first node, and the transmit path coupled to a respective out-port of the optical switch of the first node. In an alternative embodiment, a communication hub includes a plurality of neighborhood links, and a trunk coupled between the optical switch and a free space optical channel link to the network. A method of communicating in a network having plural links includes sensing the presence of a received signal failure resulting from at least one of rain and fog. The method further includes sending data in a free space optical channel of the first link when the received signal failure sensed is due to rain and sending the data in an RF channel of the first link when the received signal failure is due to fog.

Claims

1. A communication hub for providing communication paths between a remote communication network and a plurality of users, the communication hub comprising:

a plurality of neighborhood links coupled to the plurality of corresponding users in a one-to-one relationship, each link transmitting a separate, different signal to its associated user;

an optical switch including a plurality of input ports for receiving inputs from the remote communication network and a plurality of output ports coupled to the plurality of neighborhood links in a one-to-one relationship;

a free space optical channel link for communicating with the remote communication network;

a wavelength division multiplexer coupled to the plurality of input ports of the optical switch for presenting different wavelength signals to each input port; and

a trunk coupled between the wavelength division multiplexer and the free space optical channel link to the remote communication network.

2. The communication hub of claim 1 further comprising

a separate optical fiber link to the remote communication network;

and

a control switch to selectably couple the trunk between the optical fiber link and the free space optical channel link.

3. The communication hub of claim 2 further comprising a wireless network control system coupled to the control switch.