Bharti Airtel has the best mobile network in Mumbai on road – TRAI test


If you make a lot of phone calls while on the road, then Bharti Airtel is the best mobile operator for you in Mumbai, according to the results of a two-day ‘drive test’ conducted by quality auditing firm TUV SUD on behalf of the Telecom Regulatory Authority of India.

The drive test, which involved making around 500 calls per operator while driving over a distance of 300 km, also showed that Reliance GSM scored very poorly in terms of network quality.

Surprisingly, Vodafone — the market leader in Mumbai and the operator that has a reputation for having the best overal network in the city — was ranked somewhere in the middle in terms of on-road coverage. Tata DoCoMo ranked high.

It must be noted that these results are applicable only for on-road coverage. When it comes to in-building coverage, Vodafone is likely to beat all the others because only Vodafone uses 900 MHz spectrum for operating its 2G network in Mumbai.


Route for Testing for Best Network in Mumbai

Bharti also has 900 MHz spectrum, but that has been deployed for its 3G network. As a result, Bharti’s 3G signals would have better in-building penetration compared to those of the other players.

The drive test was conducted using a computer connected to several mobile phones. Each mobile phone had a SIM card from a different operator. At the same time, each mobile phone was made to dial given phone numbers and calls were connected and checked for quality.

The drive test checked for five different parameters – signal availability (coverage), call success (availability), call continuity (retainability), mobility and voice quality.

DISCLAIMER: TRAI has not clarified whether these tests were conducted on special SIMs or regular SIMs. The regular SIMs of three operators – Reliance Communications, Tata DoCoMo and Aircel – have the ability to make use of each others’ networks to make calls. As a result, even if RCom does not have signal in a particular area, the SIM will move to an Aircel network and complete the call. Whether this was being allowed to be done or not has been made clear by TRAI.



As most Mumbaikars would know, the most crucial element in all these is call continuity or the ability of the network to continue a call without dropping it.

On this criterion, Airtel came out on top. Only 5 out of 513 calls made on Airtel were dropped, implying a drop rate of 0.97%. According to TRAI guidelines, drop rate should be less than 2%, and Airtel managed to meet the guideline.

However, none of the other operators met the criteria.

The worst offenders were Idea and Tata DoCoMo and Vodafone, all three of whom dropped about 5% of the total calls that were made successfully on their network. The test calls were made for 1.5-2.0 minutes each.

Reliance GSM scored decent on this test at 2.3% call drop rate, but that is partly because the network was not available in many areas, and as such, calls drop tests could not be made at all in many areas. As a result, while everyone else had 500-550 call-drop tests done, Reliance Communications had only 393 call drop tests done. (This will be explained in the call-success test later.)



The second biggest problem faced by mobile subscribers is connectivity. Lack of connectivity can be because of two factors — lack of coverage (which was studied separately) and network congestion, which was studied separately.

Whether or not a call goes through is therefore dependent on whether coverage is there, and whether congestion is there or not.

In some cases, coverage was there, but because of high congestion, the coverage turned out to be quite useless.

For example, in Idea Cellular’s case, the operator had sufficient coverage at 95.4% of all the spots tested, but still 10% of all the calls made on its network failed to connect.

Here again, the best mobile network in Mumbai was that of Bharti Airtel. Airtel had a call success rate of 97% and signal coverage of 95.1%.

Market leader Vodafone had a call success rate of 96.1% and a signal coverage of 91.1%.

Tata GSM did pretty well for itself, with a call success rate of 95.4% and signal coverage of 97.1%.

At the bottom of the chart was Reliance Communications, which, as we have noted earlier, did pretty well on call drop tests. However, in terms of signal availability and successful connection rate, RCom did poorly. This indicates that RCom has poor network coverage, but does not suffer from congestion. If the signal is there, you can expect a smooth call.

But only if the signal is there. If there’s no signal, then there’s no call at all. RCom showed signal coverage in only 89.49% of all areas where the checks were made, coming in at the bottom of the chart. Next to RCom was Aircel, which had a respectable 93.63% coverage.

Possibly because of poor network coverage, RCom’s call success ratio was abysmal at just 68.9%. Out of 575 calls attempted on RCom’s network, only 396 calls went through.

In case of Aircel, for example, out of 550 calls attempted, 526 went through, giving it a score of 95.64%.

In network connectivity, therefore, Idea and Reliance Communications scored the lowest.



The next factor to be checked to determine the best mobile network in Mumbai was voice quality. This is determined largely by congestion, signal strength and lack of interference.

In this case, none of the six operators managed to meet TRAI’s guideline that has said that noise should be 5 or less on a scale of 0 to 7. The worst offenders in terms of quality of connection were Reliance Communications (GSM), Aircel and Idea.

The percentage of calls with good voice quality was around 85-86% for these operators.

The best operator in this respect was Airtel, on whose network, 91.1% of the calls had acceptable quality. Vodafone and Tata DoCoMo scored 89.5%.



The agency also tested a factor known as interference. Basically, in cities like Mumbai, one tower of Vodafone will be located only a few hundred meters from another tower. As a result, signals from these towers may sometimes interfere with each other.

This is particularly a problem when there are large numbers of towers. Vodafone, for example, has 4512 towers in Mumbai and Airtel has 4034. Reliance has 2,178 GSM towers, while Aircel has only 1,829 towers.

Perhaps not surprisingly, Reliance GSM scored the highest in this test. It had the least amount of ‘spill over’ and interference. 83.44% of the samples had decent levels of fidelity (lack of interference), while interference was a major issue for all other operators. Everyone else had only around 65-69% of their total samples coming in with acceptable levels of non-interference.

In the end, TRAI summed it up best: “The Drive test results revealed that most of the op erators are not meeting the benchmarks of the network related parameters. They failed to achi eve the benchmarks due to High Block Call Rate, High Drop Call Rate, Low Call Setup Success Rate &p oor Rx Quality.

“However, as mentioned earlier, this result reflects only the network conditions on the route followed by the Test vehicles and as determined during the day and time of the Drive test.”
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