Cellular communications system with sectorization

Abstract

A method and apparatus for sectorizing coverage of a cellular communications area includes providing a remote unit having microcell antenna units. Each microcell antenna unit is configured to cover a particular sector. The remote unit is connected to a sectorized base station unit which is connected to a mobile telecommunications switching office. Separate digitized streams representative of telephone signals received from the mobile telecommunications switching office are generated corresponding to the microcell antenna units and the separate digitized streams are multiplexed and transmitted to the remote unit. The remote unit demultiplexes the multiplexed digitized streams into the separate digitized streams corresponding to the microcell antenna units and the separate digitized streams are converted to RF signals for coverage of a particular sector by the corresponding microcell antenna unit. Separate digitized streams are separately generated for each microcell antenna unit representative of RF signals received at the microcell antenna unit for a particular sector. The separately generated digitized streams are multiplexed at the remote unit and transmitted to the sectorized base station unit. At the sectorized base station unit, the multiplexed digitized streams are demultiplexed into the separate digitized streams corresponding to microcell antenna units and the separate digitized streams are converted to RF signals for provision to the mobile telecommunications switching office. Diversity at the remote units is also provided.

Description

[0001]This is a division of application Ser. No. 08 / 204,660, filed Mar. 2, 1994 U.S. Pat. No. 5,627,879, which is a continuation-in-part of U.S. application Ser. No. 08 / 183, 221, filed Jan. 14, 1994, now abandoned, which is a continuation-in-part of U.S. application Ser. No. 08 / 068, 389, filed May 28, 1993, now abandoned, which is a continuation-in-part of U.S. application Ser. Nos. 07 / 946, 402, 07 / 946,964, 07 / 946,931, and 07 / 946,584, all filed Sep. 17, 1992, all of which are now abandoned. More than one reissue application has been filed for U.S. Pat. No. 5,852,651. Specifically, Reissue application Ser. No. 11 / 937,255 was filed Nov. 8, 2007 as a continuation of the present application Ser. No. 09 / 747,273.FIELD OF THE INVENTION[0002]This invention relates generally to high capacity mobile communications systems, and more particularly to a digital microcellular communication system.BACKGROUND[0003]A conventional cellular phone system 5 is shown in FIG. 1A. Such systems are currently...

AI Technical Summary

Benefits of technology

[0015]The present invention provides improved coverage and increased capacity by assignment of reusable channel sets throughout the microcell system, without the need to deploy independ

Problems solved by technology

In densely populated urban areas, the capacity of a conventional system 5 is severely limited by the relatively small number of channels available in each cell 11, 16.

Moreover, the coverage of urban cellular phone systems is limited by blockage, attenuation and shadowing of the RF signals by high rises and other structures.

This can also be a problem with respect to suburban office buildings and complexes.

While each “microcell” systems are a viable solution to capacity and coverage problems, it can be difficult to find space at a reasonable cost to install conventional base station equipment in each microcell, especially in densely populated urban areas.

Furthermore, maintaining a large number of base stations spread throughout a densely populated urban area can be time consuming and uneconomical.

The ability to analo

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