Browse Prior Art Database

IN-BUILDING WIRELESS COVERAGE USING A SECOND MODE

IP.com Disclosure Number: IPCOM000007649D
Original Publication Date: 1996-May-01
Included in the Prior Art Database: 2002-Apr-11
Document File: 3 page(s) / 188K

Publishing Venue

Motorola

Related People

Gary Grube: AUTHOR [+3]

Abstract

A common problem for people using a wireless system on the street today is that they find they cannot get good coverage into certain buildings. Most systems today are typically not designed for this. For example, many public safety state or municipal sys- tems are designed for good street and field cover- age, but not inside of buildings. Typical cellular tele- phone systems also suffer from poor coverage inside of buildings. Iridium, while providing global cover- age, will generally not provide in-building coverage.

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Technical Developments

IN-BUILDING WIRELESS COVERAGE USING A SECOND MODE

by Gary Grube, Mark Naddell and Mark Shaughnessy

INTRODUCTION

  A common problem for people using a wireless system on the street today is that they find they cannot get good coverage into certain buildings. Most systems today are typically not designed for this. For example, many public safety state or municipal sys- tems are designed for good street and field cover- age, but not inside of buildings. Typical cellular tele- phone systems also suffer from poor coverage inside of buildings. Iridium, while providing global cover- age, will generally not provide in-building coverage.

  There are methods that exist today for enhanc- ing a system's coverage to provide in-building cov- erage, however, these methods suffer t?om some prob. terns. Ofien, economics do not justify the cost of enhancing the street coverage system to also pro- vide in-building coverage across all the buildings in a given city. Instead, coverage enhancement is gen- erally done by adding local RF resources, both receiv- ers and transmitters, to cover the specific areas where coverage is most important. In the cases of micro- cellular, SpectraTAC, DigiTAC, or SmartZone sites, the resources are basically additional sites of the street coverage system, and are "wired into" the street cov- erage system's tixed network so as to extend the range ofthat system. In other words the additional resources are of the same type or "mode" as the street sys- tem. For example, to extend the coverage of an 800 MHz trunked street system, 800 MHz trunked in-building sites are added. A problem this same mode scheme often has is that these in-building sites often require additional same mode RF resources, in order to avoid interference with the existing street RF resources. Generally, frequencies used within a building must be different than those used on the street or interference will result. Additional resources of the same mode, i.e. spectrum in that band, may not be available, while second mode resources may be abundant (i.e. PCS spectrum or unlicensed spec- trum in other bands.)

  While resources in a second mode may be abun- dant, most systems today, including both the infra- structure and the subscriber units, are not built to readily accommodate operation using more than one mode. Further, for those few systems that are capa- ble of operating in more than one mode, for exam- ple a home cordless telephone that can also be used on a street cellular system, both modes must be known fitlly a priori. There is no capability to switch to anything other than one of these two specific modes.

  Thus, there is a need for a solution that easily allows a communication ,unit to use a second mode for in-building and other coverage extension require- ments. It is desired that this solution be automatic, easy to use, and economical. The solution should allow the unit to switch to any second mode, where the second mode may be, on...