Browse Prior Art Database

OPTIMAL ADAPTIVE AUDIO QUALITY THRESHOLD METHOD

IP.com Disclosure Number: IPCOM000008186D
Original Publication Date: 1997-Jun-01
Included in the Prior Art Database: 2002-May-24
Document File: 2 page(s) / 100K

Publishing Venue

Motorola

Related People

Jyh-Han Lin: AUTHOR [+2]

Abstract

A subscriber Unit Ack/Nack C/(I+N) threshold (carrier to interference plus noise threshold), depends on the fading rate of the incoming signal. The Ack/Nack C/(I+N) threshold is supposed to provide a means of insuring an "adequate" audio quality for the subscriber. However, audio quality is very subjective in an RP environment, what is considered good audio for one person might be unacceptable for another.

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0 M M-LA

Technical Developments

OPTIMAL ADAPTIVE AUDIO QUALITY THRESHOLD METHOD

by Jyh-Han Lin and Samir Sawaya

INTRODUCTION

  A subscriber Unit Ack/Nack C/(I+N) threshold (carrier to interference plus noise threshold), depends on the fading rate of the incoming signal. The Ack/Nack C/(I+N) threshold is supposed to provide a means of insuring an "adequate" audio quality for the subscriber. However, audio quality is very subjective in an RP environment, what is considered good audio for one person might be unacceptable for another.

  Rather than assigning a "static" c/(I+N) threshold for each fade rate condition, system wide, to the subscriber unit, we are proposing that each individual subscriber unit determine the appropriate C/(I+N) threshold that is acceptable to the user of that subscriber unit for each fade rate condition (Immobile/walking/in vehicle). Currently, the subscriber unit can determine the level crossing rate

(or the fade rate) around an average received signal level. The subscriber unit stores in a memory, either a table of fade rate vs. required C/(I+N) threshold at a particular frequency, or a function relating the two. When the fade rate is determined, the sub- scriber unit can then set an appropriate C/(I+N) threshold forACK/NACK purposes.

  This article describes how a subscriber unit "learns" an appropriate C/(I+N) threshold table or function that suits the taste of a particular user. One way to accomplish this is as follows:

ADAPTIVE LEARNING

  The learning period will be a randomly selected time period (either by the PMU or the Infrasturcture equipment). During this randomly selected time period, the PMU will learn the message acceptability level of each individual user.

minimum

- . _ _. I C/(N+Il

floor curve

Fig. 1 Level Crossing Rate

e Motorolq Inc. ,997 107 June 1997

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@ MO-LA Technical Developments

  For the initial learning period, the C/(I+N) thresh...