"It is difficult to maintain a view of a collapsing Chinese economy when 20 million people - or close enough to that number - are walking into a China Mobile shop every month and purchasing a new phone," Chris Lane, a senior analyst at Bernstein Research, said in a report.

"Each of those subscribers is putting cash down for a new phone, increasing data usage and spending more than they did the year before."

For market analysts, the monthly growth rate of 4G subscribers on the mainland serves as a gauge of what matters most right now for Chinese consumers.

"Upgrading your cell phone is an easy decision to defer if you're worried about your job, your income or your [stock] portfolio," Lane said. 

"It is an equally easy 'treat' if things are going well."

China Mobile, the world's largest wireless network operator by number of subscribers, added 19.2 million new 4G users in July. That was down marginally from 19.3 million in June, but the third-highest monthly addition to date. The operator signed up a record-high 19.7 million new 4G subscribers in March.

Bernstein estimated that China Mobile, which had 818.8 million total cellular subscribers as of July 31, could have around 300 million 4G users by the end of this year, up from 90 million last December 31. 

The operator's 4G infrastructure is built on the indigenously developed 4G standard called time-division long-term evolution (TD-LTE). 

All three telecoms operators in mainland China received their TD-LTE licenses in December 2013. 

But China Unicom and China Telecom could not deploy their 4G networks at the same time as China Mobile because their 3G networks are more technically suited for upgrading on the mature 4G standard frequency-division duplex long-term evolution (FDD-LTE).

Early this year, both China Unicom and China Telecom started deploying "hybrid" 4G networks, which combine both TD-LTE and FDD-LTE infrastructure, in a number of cities permitted by regulators. 

"Robust 4G adoption is coming with higher monthly average revenue per user (arpu) numbers amid relatively benign competitive dynamics and mandated cost discipline," Anand Ramachandran, the head of Barclays' telecoms, internet and media equity research for Asia, excluding Japan, said in a report.

Subscribers on 4G networks are typically always online and consume more data, thus having higher-than-average arpu profiles compared to mainland China's 584.9 million 2G mobile users at the end of July.

While 4G adoption has grown in China, monthly 4G arpu among the three operators appears to have decreased from 140 yuan (US$22) early last year to about 100 yuan at present.

Bernstein's Lane, however, said falling arpu was not a problem. Rather, it was an expected outcome from the rapid adoption of 4G services. 

"New lower-value 3G customers are upgrading to 4G services and spending more as a result," Lane said. 

"However, they are still spending less than the higher-value, early 4G adopters - leading to falling 4G arpu."

He said most customers who have recently upgraded their mobile service start with low arpu, but generally increase their monthly spending over time as they develop their online access and data-consumption habits.

Along with the accelerated 4G network coverage across the country, mobile users are also being encouraged to upgrade their service by more affordable and advanced smartphones.

"Over 98 per cent of new smartphones being sold are 4G-compatible, and the cost of 4G models has fallen substantially," Lane said. 

"China Mobile, for example, now has a 4G model available for 280 yuan [US$44]." 

Based on the assumption that most active mobile users in China replace their handsets every two years, Bernstein calculated that the 508 million 3G users in the country at the beginning of this year will likely purchase a new smartphone by the end of 2016.