Technical aspects

Methodology

     Fundamentals

This study?s methodology is based on 3 fundamentals:

a) End-to-end measurements: The measurements are made between terminal points of the same mobile network;

b) Impartiality: The measurements are made simultaneously, in time and space, for the three operators (OPTIMUS, VODAFONE and TMN), thus guaranteeing equality of testing conditions;

c) Objectivity: The tests are carried out in a totally automatic way, eliminating the subjectivity inherent to human intervention or decision. 

    Quality of service indicators

This study analyzes indicators of basic importance, considering quality from the user?s standpoint:

a) SMS Accessibility: the probability of success in sending an SMS, i.e., the ratio of the number of successfully sent SMS (SMS  received at the Message Center) and the total number of messages sent.

b) SMS delivery time: Time elapsing between the successful sending of an SMS by the origination terminal and this very SMS?s reception by the destination terminal.

c) SMS delivery rate: Ratio of the number of SMS received at the destination terminal and the number of SMS sent by the origination terminal.

Doubled SMS, error SMS and SMS not delivered within a previously-defined time frame will not be taken into account.

An error SMS has at least one incorrect bit upon reception.

The time frame for delivery of an SMS will be 175 seconds, as specified by ETSI European Telecommunications Standards Institute (TS 102 250-5 V1.1.1 (2004-09)).

    Measurement procedures

Testing to the Short Message Service (SMS) is performed under the following conditions:

1. Between terminals of the same Mobile Network (Mobile-Mobile);

2. The terminal equipment is kept motionless in locations with adequate coverage.

3. Terminals work as SMS senders and receivers;

4. Interval between a terminal?s consecutive SMS sendings is 70 seconds, as specified by ETSI European Telecommunications Standards Institute (TS 102 250-5 V1.1.1 (2004-09));

5. The time frame for delivery of an SMS is 175 seconds, as specified by ETSI European Telecommunications Standards Institute (TS 102 250-5 V1.1.1 (2004-09)).

Tested areas

On this first monitoring of the Short Message Service (SMS), test and measurement equipment was placed at locations with adequate mobile coverage, in the cities of Lisbon and Porto.

Sample size

In order to analyze the networks? behaviour in time (busier hours vs. empty hours; week days vs. weekends), the tests were performed continuously during one week.

Thus, the sample shown on Table 1 was obtained considering the interval between consecutive SMS sendings and also the simultaneous sendings from terminal equipment placed in Lisbon and Porto.

Test and measurement equipment

For the conduction of these tests, ANACOM used the DATAMAT M366plus testing and measurement equipment, which is a Quality of Service analyzer for GSM networks.