Few Urban Sites in Delhi, Mumbai Cause Most of the Call Drops

A new report on call drops in India, published by the Telecom Regulatory Authority of India, suggests that some mobile operator sites have no particular call drop issues, while others have significant problems, based on TRAI drive tests as well as analysis of performance records regularly submitted to TRAI by mobile operators.

Those findings mirror what one would expect, in terms of general problems caused by networking loading and congestion in any urban area: one or two percent of cell sites cause most of the problems.

TRAI’s study of call detail records from mobile operators in Delhi showed problems at six out of 8604 sites operated by one supplier;  10 out of 15850 for a second operator and 504 out of 16117 sites for a third operator.

In other words, the towers where call drop standards exceed TRAI standards (two percent or fewer dropped calls) are very few in number, compared to the total number of sites examined by TRAI.

Specifically, though for one operator about three percent of sites were problematic, two other mobile operators had problems with quality at just 0.06 percent or 0.07 percent of sites.

Weak signal strength, though not the only cause of call drops, is a big factor. Radio link failure also was found to be a big issue.

Mobile Operator Cell Sites with Call Drop Problems in Delhi, Based on Call Detail Records
Operator	Problem Sites	Total Sites	% of Total Sites
1	6	8604	0.07
2	10	15,850	0.06
3	504	16,117	3.13
source: based on TRAI data

A different analysis based on cells with three percent call drop rates at any hour of the day showed one operator with 108 out of 8604 sites affected; a second operator with 106 out of 15850 sites exceeding the three-percent threshold; while a third operator had call drop issues of three percent or more at 335 sites out of 16117 locations.

In other words, cell locations that exceeded three percent call drops at any hour of a typical day represent less than one percent to a maximum of two percent of sites.

Sites Exceeding 3% Call Drops at Any Hour of a Day
Operator	Problem Sites	Total Sites	% of Total Sites
1	108	8604	1.3
2	106	15,850	0.7
3	335	16,117	2.0
source: based on TRAI data

In a statement that mobile operators and TRAI can agree on, the report says “there is an urgent need to increase the number of the towers.” The full report also shows that blocked calls are an issue, not simply dropped calls.