Call drops in mobile wireless networks: Calling your attention

(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:
  1. Credit of talk-time in minutes/ seconds
  2. Credit of talk-time in monetary terms
  3. 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.


  2. Consultation Paper on Compensation to the Consumers in the Event of Dropped Calls.

DSC_0013aMamidala 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

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6 Responses to Call drops in mobile wireless networks: Calling your attention

  1. Ravi Ranjan says:

    One way to reduce congestion is to charge differently during peak hours say 7 – 9 PM and non-peak hours (rest of the day). if charges during peak hrs are 1.2 times the nonpeak hrs, people will make only necessary calls during those hours and hence with less traffic, call drop rate will decrease. though regulations are strict related to pricing but coming up with innovative pricing may help. example may be to charge more for more than 3 calls after 7 pm and so on. Uber and ola charge differently at peak hrs and at times they even charge twice.

  2. If you recall, we used to do that long ago for fixed line phone calls. There used to be long queues at telephone booths after 11pm to make calls at a lower price….

  3. Shailesh Jha says:

    Its a serious issue for the user as Company never towns responsibility. Rather they used to make some excuses like network problem or may be quite lame excuses which even a layman can’t digest. These telecom industries are making huge profits due to these paucity and loopholes in policy framework. GoI should start implementing fines and other charges to these companies so that they will treat their customers as a customer not merely as a market.
    Though BSNL have even waived off any roaming charges, these private companies are not at all in mood of doing so as they know BSNL have certain limitations and that’s why their current users will not opt for BSNL but TRAI need to come up with a solution. This issue is being highlighted and in limelight since a year or so still TRAI is unable to implement it fully. Roaming charges are a huge burden on users as we as a user used to travel different places and have to make frequent calls during these periods without having any concern on bills. There are lot other things which TRAI have to seriously intervene into and regulate the policies at very ground level like the case of Internet (2G/ 3G/ 4G or even dongles) are worst. I am experience a pathetic internet service from TATA (Max WiFi) and customer care or even their top management are not at all bothered about number of complaints.
    Hope TRAI will come up with a concrete policy to take care the rights of customer and regulate these service providers.

  4. Sriram says:

     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.

    No. I am playing devil’s advocate here

    This has to be treated on a case by case basis. This is where a Telecommunications Industry Ombudsman can be very handy. Is there one in India?

    No matter what you do there will be call drops in a mobile network. The solution being proposed above is only speaking from a billing perspective alone. The solution has to include a billing perspective, a technology perspective and a customer rights and operators rights perspective.

    The above scenario of a call drop 5 seconds after setup can happen in many circumstances where it is not the operators fault. For example

    1. If a customer has a faulty handset. Is it fair to blame the operator for it? Of course not
    2. If a customer experiences a call drop inside a lift or a Faraday Cage Like environment or at a known edge of coverage location? Of course not
    3. External Interference. If defence equipment transmitted in frequency bands allocated to mobile operators that causes call drops and call setup fails. Avionics equipment and Navy equipment in particular annoy me often as it sends my network performance stats into a tizzy. How effectively is this being policed in India and how empowered is TRAI in shutting down sources of external interference? In Australia we have the ACMA for the same.
    4. Calls drops in a known poor coverage area where there has been community opposition to deploy a mobile site-: Is it fair to blame an operator to have not acquired a site in such an area? Of course not. How many mobile towers are located inside IIT Delhi? Is the campus being served predominantly from sites located outside the campus or is there good site density inside the campus? If not is it an operator’s fault? Of course not.

    The list can go on and I can keep sulking about why it is not my fault till the cows come home.

    The above proposal I think is extremely cumbersome and impractical to implement into billing systems. I think a customer should be entitled to a refund only if he/she has been sold a service in an area with known coverage or performance issues and the operator has not taken any steps to improve customer experiences. This is particularly where an Ombudsman can be of help to the Indian citizen to keep operators in check. Operators need to invest more in customer experience teams willing to visit customer locations and provide solutions on a case by case basis.

    If I am correct most of Indian traffic is on GSM. Calls drops will be lower in 3G due to better spectrum efficiency of the technology but 3G being an expensive technology and India being a low ARPU(Average Revenue Per User) market, 3G I don’t think really took off. Today mobile services are more data driven. TRAI should weigh into the benefits 4G has to offer, review spectrum situation in India and strongly support the extensive rollout of 4G services including VOLTE (Voice Over LTE). 4G is cheaper to roll out than 3G and this is where the future lies. TRAI, Telecom ministry and Operators need to carry the Indian subscriber forward into the 4G era.

  5. Sriram says:

    From a fair competition point of view I think the Indian Mobile operators are not competing on a level playing field. To a large extent that Government and TRAI need to promote and police that. Without getting into the politics of spectrum allocation let us just look at it from what Radio Waves do.Frequency and Wavelength are inversely proportional. The 850 and 900 MHz bands will propagate further compared to 1800 MHz or 2100 MHz. From the old GSM days operators first started out with 900MHz bands to establish large presence and then added 1800 MHz for capacity relief. Incumbents like Bharti, BSNL and Reliance have the wealth and the infrastructure to afford both bands. So any new entrant in the Indian telco space generally went for a GSM1800 spectrum license as 900MHz was exhausted (if I am correct). So for a new entrant with 1800 MHz spectrum alone to be able to demonstrate good network performance he/she needs to build many more 1800 sites in order to match an incumbent’s coverage footprint meaning larger capital and operational expenditure. There in lies the governance problem. There needs to be a well defined demarcation between promoting competition and offering quality networks to Indian subscribers. Hence I feel a technology change towards 4G needs to be promoted and embraced by all and this has to be done with a fairer spectrum allocation and with a view towards a GSM shut down date. There needs to be a cap on the number of players in the market. Each bidder bids for a portion from the 850 or 900 MHz bands and also from 1800 and 2100 MHz bands so that they can address coverage and capacity goals by balancing traffic between low and high bands. In summary to overcome this dropped calls problem everyone i.e. the subscribers, operators and TRAI, government need to look and move forward. I have said it before and I say it again 4G is the way forward.

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