Browse Prior Art Database

Cellular Infrastructure Automated Self-Test

IP.com Disclosure Number: IPCOM000016705D
Original Publication Date: 2003-Jul-09
Included in the Prior Art Database: 2003-Jul-09
Document File: 2 page(s) / 77K

Publishing Venue

Motorola

Related People

Neil Turner: AUTHOR [+2]

Abstract

This paper shows how an rf expansion path between two cabinets of cellular infrastructure equipment can be checked using a straightforward procedure. This allows the interfaces between units to be tested and characterised automatically to ensure integrity.

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Cellular Infrastructure Automated Self-Test

Neil Turner, Michael Perdikakis

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Abstract

This paper shows how an rf expansion path between two cabinets of cellular infrastructure equipment can be checked using a straightforward procedure. This allows the interfaces between units to be tested and characterised automatically to ensure integrity.

Introduction

Cellular infrastructure rf equipment is generally housed in an equipment cabinet containing multiple rf transceivers, duplexers and potentially a receiver switching matrix to route signals between the antennas and the receiver inputs in the transceiver units.

Problem to be Solved

These BTS cabinets generally have high levels of internal rf self-test using loopback to check the integrity of signal paths.  Antenna VSWR can also be measured to detect faults.

However, it is possible to take an rf output from the rx switching matrix into another cabinet, so that more uplink calls can be processed (see diagram in Figure 1).  Essentially, more calls can be handled by linking the antennas into a second or third cabinet.  By setting each transceiver to a different frequency, more users can be accommodated.  However, it is difficult to test the quality of the rf link between the cabinets – the expansion path is not usually tested as part of the loopback capability so its integrity cannot be guaranteed as part of the automated checking.

Solution

A simple solution is available for this problem.  Consider the diagram in Figure 1.  This is a highly simplified, generic, representation of the system, with 2 cabinets linked using an rf cable.  There may be multiple links, for main and diverse channels, or multiple links for multiple antennas.  The expansion path may also include other LNAs, switches, or other functionality.  These have been omitted for clarity.

Examine the path in cabinet with the splitter.  The transceiver connected to the antenna via the switching matrix will be able to determine received signal levels via the receiver GSM RXLEV function, or equivalent.  Under normal operation, the radio in the second cabinet attached to the expansion path will be on a different rf channe...