Apple iPhone 7 Plus smartphones with Intel modems sold in the UK struggle with less than perfect signals

There may be a good reason why your shiny new iPhone struggles with poor reception

Research by Cellular Insights suggests that Apple iPhone 7 Plus devices with Intel - rather than Qualcomm - modems provide significantly poorer internet connections with anything less than a perfect mobile signal.

And iPhone 7 Plus users in the UK will be affected due to the supply decision by Apple, with only models sold in China, Japan and the US coming with more tried-and-trusted modems made by Qualcomm.

Qualcomm has been the sole supplier of modem technology to Apple for the past five years but, in a bid to diversify its supply it brought in Intel to provide modems on the iPhone 7 Plus, launched this summer.

Qualcomm's X12 Category 12 integrated modem is capable of up to 600 megabits per second (Mbps) at peak downlink speeds, with Apple utilising some, but not all, of the features it offers: namely, three-way carrier aggregation on the downlink and two-way carrier aggregation on the uplink for contiguous Band 7 or Band 41.

"Therefore, the peak theoretical downlink speeds are limited to 450Mbps when aggregating three 20MHz wide LTE component carriers," according to Cellular Insights.

The Apple ‘win' for Intel, it adds, is the company's first major design win in some time and may even be a ‘make or break' moment for Intel's mobile modem business. A number of markets and carriers have been supplied with iPhone 7 Pluses bearing the Intel, rather than the Qualcomm, part.

Cellular Insights acquired a number of iPhone 7 Plus devices from different sources and ran a series of tests on them at different LTE bands. It found that, across the range of devices, the iPhone 7 Plus offered similar network performance under ideal conditions.

However, as the network conditions were reduced, the iPhone 7 Plus with the Intel modem on board deteriorated at a faster rate than the iPhones with the Qualcomm modem.

"Most of the time mobile operators get blamed for dropped calls or session timeouts, but it's often forgotten that the phone OEMs implementation of baseband, RF Front-End (RFFE), and the antenna design could play its role," suggests Cellular Insights' technical report.

It added: "In all tests, the iPhone 7 Plus with the Qualcomm modem had a significant performance edge over the iPhone 7 Plus with the Intel modem. We are not sure what was the main reason behind Apple's decision to source two different modem suppliers for the newest iPhone.

"Considering that the iPhone with the Qualcomm modem is being sold in China, Japan and in the US only, we can not imagine that modem performance was a deciding factor."

iPhone 7 Plus or Samsung Galaxy S7 Edge? Computing's sister site V3 put the two high-end smartphones head-to-head.