KARACHI, Feb 21: The Pakistan Telecommunication Authority on Monday carried out a survey of the performance of the three cell phone companies operating global system for mobile (GSM) networks in the city.

The telecommunications regulator initiated the fourth survey of the performance of cell phone operators on Feb 16.

The PTA regional director, Col Rizwan Hydri, drove to various areas of the city as three cars, each containing a PTA official and a cell phone company representative, followed him.

The PTA officials made calls to one another and to their colleagues either at the headquarters or driving in other areas as part of mobile teams. The areas covered by the surveyors included Kalapul, Korangi Industrial Area, Landhi Industrial Area, Quaidabad Bridge, Malir, Kalaboard, Model Colony, Malir Cant, University Road, Gulistan-i-Jauhar, Dalmia Road, Dhoraji, Stadium Road, Bahadurabad and Sharfabad. The cellphone operators whose performance came under scrutiny were Paktel, Ufone and Mobilink.

The PTA regional director told Dawn that the cellphone company representatives had been asked to switch off their mobile phones so that they could not inform their firms about the localities being surveyed. He added that they had also not been informed about the areas which were visited during the survey.

The PTA officials who carried out the survey told Dawn that the parameters evaluated by them included network accessibility, access delay, service accessibility, call retainability, speech quality, service access SMS and access delay SMS.

They said they changed their cell phones regularly to better evaluate the performance of cell phone companies. They added that they bought SIMs available on the market.

The PTA officials said three parameters constituted speech quality: echo, noise and voice chopping. They said while it was easy to determine echo and noise, evaluating the intensity of voice chopping was difficult. This they did by counting numbers from one to 10.

They said that the marks given by them and the persons to whom calls were made, were averaged and the number thus obtained was referred to as "mean opinion score." The representatives of the cell phone companies closely observed how the PTA officials carried out the survey.

They told Dawn that while they were satisfied with manner the survey was done on the whole, it was beyond them why the performance of their cell phones were evaluated in areas where they were not allowed to establish their networks. They added that most of them were restrained from establishing their BTS, known as antennas in common parlance, in Malir Cantt.