Optical simulcast network with centralized call processing

• US 6,504,831 B1
• Filed: 02/23/1999
• Issued: 01/07/2003
• Est. Priority Date: 02/23/1999
• Status: Expired due to Term

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Greenwood, Ken C., Slabinski, Richard P., DeVinney, Erik T.
• Primary Examiner(s): CUMMING, WILLIAM D
• Application Number:
  US09/256,244
• Time in Patent Office: 1,414 Days
• Field of Search: 370/342, 370/327, 379/111, 340/505
• US Class Current: 370/342
• CPC Class Codes: H04B 10/25755 Ring network topology

Abstract

A system for distributing radio frequency signals in a wireless communication network that provides an economical method of establishing and then later enhancing network coverage and capacity. The system centrally deploys Base Transceiving System (BTS) equipment and distributes their signals through a fiber network to individual cable microcell integrators (CMI) associated with the individual cell sectors of the system. The CMIs contain filtering equipment that permit them to be assigned in simulcast groups, depending upon the desired network capacity. For example, in an initial build out situation, a large number of CMIs operate at a common carrier frequency, modulation code, and/or code phase. As network demands increases, additional capacity is provided by reprogramming filters and/or signal processors in the CMIs. The approach results in high utilization of centrally located BTS equipment, avoids the need to re-engineer or redeploy additional RF equipment after an initial design phase, and has an added benefit of improved backhaul trunking efficiency while avoiding the need to deploy both fiber and cable physical media at the remove sites.

Claims

1. A wireless communication system in which a plurality of cells are located substantially adjacent one another, the wireless communication system operating over a specified frequency range to provide signals in a forward direction from a central base transceiver station towards subscriber units located in the cells, the system comprising:

a hub interface converter, for accepting radio frequency signals from at least one base station, the radio frequency signals comprising at least one base station traffic signal modulated onto a radio frequency carrier (RF), for upconverting such radio frequency signals to an optical frequency carrier signal, and for coupling such optical frequency carrier signal as an optical forward transport signal onto an optical fiber;

an optical fiber for distributing the optical forward transport signal;

a plurality of optical splitters connected to the optic fiber; and

a plurality of cable integrators, each receiving the optical transport signal from one of the splitters, each cable integrator associated with a respective one of the cells, each cable integrator further including an optical demodulator to translate the optical forward transport signal to corresponding transmit radio frequency signals such that the transmit radio frequency signals in at least two cells have the same radio frequency carrier.

2. A system as in claim 1 wherein the hub interface converter additionally comprises:

a plurality of RF down converters, each RF down converter for translating radio frequency energy in a forward link radio frequency bandwidth including the radio frequency carrier to an output intermediate frequency signal at an intermediate frequency carrier;

an RF combiner for combining the output intermediate frequency signals from multiple RF down converters to produce a combined RF signal; and

an optical modulator for upconverting the combined RF signal to produce the optical transport signal.

3. A system as in claim 1 wherein the cable microcell integrator further comprises:

an optical detector for receiving the optical forward transport signal from the optical cable as a detected signal; and

an RF upconverter for converting the detected signal to a radio frequency carrier within a forward link radio frequency bandwidth.

4. A system as in claim 1 wherein the cells are divided into sectors, and where cable integrators are deployed in two or more adjacent cell sectors.

5. A system as in claim 1 wherein the cells are divided into microcells, and wherein cable integrators are deployed in two or more adjacent microcells.

6. A system as in claim 1 wherein Code Division Multiple Access (CDMA) is used to modulate the traffic signals onto the radio frequency carrier signals, and wherein the transmit radio frequency signals in at least two cells have the same code.

7. A system as in claim 1 wherein Code Division Multiple Access (CDMA) is used to modulate the traffic signals onto the radio frequency carrier signals, and wherein the transmit radio frequency signals in at least two cells have the same code phase.

8. A system as in claim 1 wherein the cable cell integrators additionally include optical modulators for accepting subscriber radio frequency signals from the subscriber units, and upconverting the subscriber radio frequency signals to an optical frequency carrier signal as an optical reverse transport signal coupled to the optical fiber.

9. A system as in claim 8 wherein the hub interface converter additionally comprises an optical demodulator to translate the optical reverse transport signal to corresponding radio frequency signals within a reverse link bandwidth which are in turn coupled to one or more of the base stations.