(To appear in Sept-Oct 2015 issue of IETE Technical Review)
After intense debates over net neutrality, the issue of call drops in mobile networks has now become a new burning topic in public discourse. Whether you have called another user or someone else has called you on your mobile phone, if the call is interrupted before the users decide to terminate the call, it is known as a call drop. A dropped call directly affects the quality of service (QoS) that is expected to be maintained in a mobile wireless network. Call drops are more worrisome than blocked calls since a call drop is no longer in the queue to re-establish the connection. The call drop rate (CDR) is, therefore, used as one of the essential figures of merit to measure the quality of service in mobile wireless networks.
Call drops are rare in fixed line networks. For most users, since the mobile wireless network is only an extension of the fixed line network, they expect the same quality of performance in mobile networks as in fixed line networks. In future, this demand for improved quality of service will further increase as most people’s lives will revolve around services provided by the mobile wireless networks.
Every service provider in India furnishes, among other quality parameters, the monthly call drop data to the Telecom Regulatory Authority of India (TRAI). Monthly data from most of these service providers indicated that the call drop rate is less than 2%, a limit prescribed by TRAI. If the call drop rate is less than 2% as claimed by the service providers, such a low call drop rate should not significantly affect the user experience. However, a nationwide outcry on frequent call drop complaints prompted TRAI to carry out their own measurements in two big cities – Mumbai and Delhi. To every one’s surprise, the data collected by TRAI showed a different picture – the call drop rates varied from 0.84 % – 17.29 % in Delhi and 0.97 % to 5.56 % in Mumbai among different service providers. Except for one out of six, all the five service providers crossed the 2% limit, some very significantly. A similar situation could exist in other parts of the country.
In addition to the inconvenience caused to the user, the call drops will also lead to additional charges to the user since the user will attempt to call again to continue the conversation. Since nearly 41 % of the mobile users in India pay the charges on a per-minute-pulse rate, call drops will lead to an unnecessary financial burden to the user. In per-minute-pulse scheme, the users have to pay even if they establish the connection for one or more seconds before the call drops. The user, therefore, is the sufferer. Even for the remaining 59% of the users, who use the pay-per-second scheme, it is not that call drops will only cause inconvenience but it will also lead to a monetary loss to the user since the user will spend more time during the follow-up call to compensate for the interrupted conversation. Such call drops can seriously undermine productivity and efficiency in professional dealings.
Call drops can typically be avoided if service providers take some measures such as optimal balancing of traffic among the different frequency layers, minimizing interference and congestion and maximizing the service area. Therefore, within the available spectrum, the quality of service in mobile networks can only be increased by improving the network infrastructure and by deploying technological solutions to minimize the call drops. However, TRAI has pointed out that while the minutes of usage by mobile users has grown by 6.8% during the last couple of years, the investments made by the service providers has only increased by 4.6 % during the same period barring the investments made to purchase the spectrum. This mismatch between usage growth and investments in network infrastructure needs to be bridged since the quality of service problem will boomerang in future as the mobile network user base increases.
While the service providers, hopefully, make efforts to improve their infrastructure, can something be done to help the consumers?
In a recent consultative paper, TRAI has posed two important questions, among others, to all the stake holders – consumers and the service providers.
- Do you agree that calling consumers should not be charged for a call that got dropped within five seconds? In addition, if the call gets dropped any time after five seconds, the last pulse of the call (minute/second) which got dropped, should not be charged. Please support your viewpoint with reasons along with the methodologies for implementation.
- Do you agree that calling consumer should also be compensated for call drops by the access service providers? If yes, which of the following methods would be appropriate for compensating the consumers upon call drop:
- Credit of talk-time in minutes/ seconds
- Credit of talk-time in monetary terms
- Any other method you may like to suggest
All of us should proactively come forward and provide our views and suggestions to help the regulator to form a policy so that consumer satisfaction is restored without any delay.
- Consultation Paper on Compensation to the Consumers in the Event of Dropped Calls. http://www.trai.gov.in/Content/news/71293_0.aspx
Mamidala Jagadesh Kumar is a Professor of Electrical Engineering at the Indian Institute of Technology, New Delhi, India. He is the Editor-in-Chief of IETE Technical Review and an Editor of IEEE Transactions on Electron Devices. He has widely published in the area of Micro/Nanoelectronics and is known for his excellence in teaching. He is a member (PT), Telecom Regulatory Authority of India (TRAI). More details about Dr. Kumar can be found at http://web.iitd.ac.in/~mamidala