Call drops - Are substandard phones really the cause?
I write in reaction to an article published on page 38 of the Daily Graphic on April 5, 2014. According to the report, Mr Kwaku Sakyi–Addo, the Chief Executive Officer (CEO) of the Ghana Chamber of Telecommunications (GCT), made a statement to the effect that “sub-standard phones were a major contributory factor to call drops in the country.
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Fake phones were usually composed of bad earpieces and poor batteries, and as a result, choked the network. ” Furthermore, he stated that “about 25 to 30 per cent of substandard phones contributed to drop in calls, and it disallowed those with the appropriate phones to make calls”.
Technically, these statements are misleading and seek to blame subscribers for their inability to reduce call drops on their networks. This article, therefore, seeks to briefly explain such a highly technical phenomenon in simple terms for the benefit of subscribers.
The design of such networks is based on a cellular architecture. The geographic area within which mobile units (mobile phones and other mobile devices) can communicate with a particular base station is referred to as a cell. Each of these cells has a base station, which provides access for the mobile units to a backbone wired network.
All base stations within a given region are connected to a mobile telephone switching office (MTSO), which acts as a central controller. A set of channels (frequencies) is allocated to each base station. Neighbouring cells use different channels in order to avoid intolerable interferences.
One of the reasons why mobile phones have become so popular is the fact that users can make and receive calls while on the move. This is made possible by a technique known as handoff in mobile communication networks.
Handoff is simply the process of transferring an ongoing call from one cell to another cell as the user moves through the coverage area of the cell. It is initiated when the signal quality of a mobile unit to its base station decreases below a given threshold. This usually occurs when the unit moves between cells and can also be caused by fading or shadowing within a cell.
When a mobile user wants to communicate with another user or a base station, it must first obtain a channel from one of the base stations that hears it (usually, it will be the base station which hears it the best). If a channel is available, it is granted to the user. In the case that all the channels are busy, the new call is blocked. This kind of blocking is called new call blocking. Other users who have access to channels may release their channels under either of the following scenarios:
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1.Completion of a phone call
2.Movement into another cell before a current call is completed.
While performing handoff, the mobile unit requires that the base station in the cell that it moves into will allocate it a channel. If no neighbouring base station has available channels of acceptable quality, then the handoff attempt fails and the call will be dropped. This kind of blocking is called handoff blocking and it refers to blocking of ongoing calls due to the mobility of the users.
Are sub-standard phones really the cause of call drops?
I have already enumerated the various challenges of wireless communication systems and how these affect call drops. Engineering solutions to these challenges should come from the operators. Excellent radio planning and optimisation and robust network design to ensure less blocking at switches will enhance the QoS.
Currently, all cell phones have the same power amplifier and barring a short in the phone or physical damage, the phone’s transceiver is usually not the culprit of poor reception and rarely the cause of dropped calls.
When it comes to call drops, one struggles to understand how “substandard phones” are a major contributory factor to call drops in the country. I wonder the kind of study that was done to prove that “about 25 to 30 per cent of sub-standard phones contributed to drop in calls, and it disallowed those with the appropriate phones to make calls”.
These are serious statements without any technical proof. When it comes to call drops, the base stations and switching centres are the culprits as explained earlier in this article.
I wonder if Ghana has standards for mobile phones imported into this country just as other commodities. If these standards exist, do the regulatory authorities have access to testing facilities to ensure imported phones meet those standards? If the answer is no, then how can anyone say for sure that a given phone is substandard? We should not try to confuse the quality of the product with a given standard.
What we, as a country, should be considering when it comes to the issue of fake phones is the standard for Specific Absorption Rate (SAR), which is a measure of the amount of radio frequency energy absorbed by the body when using a mobile phone.
Conclusion
“Substandard or fake phones” have no role in “contributing to drop in calls, and disallowing those with the appropriate phones to make calls”. The only concern we should have with these so called “- phones” is their SAR, which have health implications for users. Mobile phone operators must sit up to improve the quality of service for subscribers in the country. They should find innovative ways of meeting customer expectations.
Majority of subscribers in the country are prepaid, which means they pay for the service even before delivery. The NCA should, therefore, ensure customers are not short-changed by operators by the provision of sub-standard services.
• The writer is a lecturer / University ICT Consultant at Department of Computer Engineering College of Engineering Kwame Nkrumah University of Science and Technology (KNUST) Kumasi - Ghana