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AN ALGORITHM DESIGNED TO AUTODETECT AND DISABLE NOISY CHANNELS IN A 2-WAY COMMUNICATION SYSTEM

IP.com Disclosure Number: IPCOM000009632D
Original Publication Date: 2000-Jan-01
Included in the Prior Art Database: 2002-Sep-05
Document File: 2 page(s) / 104K

Publishing Venue

Motorola

Related People

Mark Bogus: AUTHOR [+2]

Abstract

In a wide area digital private trunked system, such as a Motorola SmartZone system, the system consists of many RF channels. These channels operate as FDMA and use separate frequencies for both transmit and receive. These channels operate in a noisy environment susceptible to interference from many sources. Thus, these resources must be continuously monitored by the fixed end to deter- mine malfunctions and other errors. When errors occur, the channel is disabled and alarm messages generated to alert repair personnel. These resources arc also maintained on a regular basis to ensure opti- mal functionality.

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0 M MO-LA Technical Developments

AN ALGORITHM DESIGNED TO AUTODETECT AND DISABLE NOISY CHANNELS IN A 2-WAY COMMUNICATION SYSTEM

by Mark Bogus and Jim Edkins

BACKGROUND

  In a wide area digital private trunked system, such as a Motorola SmartZone system, the system consists of many RF channels. These channels operate as FDMA and use separate frequencies for both transmit and receive. These channels operate in a noisy environment susceptible to interference from many sources. Thus, these resources must be continuously monitored by the fixed end to deter- mine malfunctions and other errors. When errors occur, the channel is disabled and alarm messages generated to alert repair personnel. These resources arc also maintained on a regular basis to ensure opti- mal functionality.

PROBLEM

  The problem, however, is when these RF resources are not properly functioning, or more specitically, interference from other systems occurs such as spurious RF emissions, noise from industrial machinery, etc, impede their performance. These events can occur on regular intervals, or more typi- cally irregularly. The only indication is degraded system performance and customer complaints. There are some mechanisms currently deployed that mitigate some of this problem. If a signal is detect-

ed on a RF channel without reason (no assignment), the signal is not allowed to be repeated throughout the system.

  Additionally, after a period of time, the channel is taken out of service. If the signal is no longer detected after a period of time, the channel is returned to the system for use. This type of detec- tion is effective for very severe or significant levels of interference. It does not, however, measure a quality of service for the channel. It merely detects illegal signals on the channels. That can lead to assigning voice and or data calls on RF channels that are impaired, but not detected by this mechanism.

SOLUTION

  The solution to this problem is to monitor the channel for several pieces of critical information and use these to determine if the channel is available for service. There are two significant pieces of information necessary to determine the quality of a channel, BER (bit error rate) and received signal level, or RSL. The system analyzes both sets of dam to determine the quality of the...