China Mobile now seems to be recognizing that it can't solve its data capacity demand issues through macrocells alone. With a low takeup of their 3G service (less than 10% of subscribers), the strain on their huge GSM network is taking its toll. As with many other network operators elsewhere, their strategic plan involves a combination of 2G, 3G, 4G and Wi-Fi but critically, they recognize that small cells have an essential role to play and have been moving forward with trials and deployments.

Quick recap on the Chinese Network size and scope

It's been some time since we reviewed the status of femtocells and small cells in China. In a country of over 1 billion people, the three national network operators there have unbelievably large customer numbers. All compete for both fixed and mobile services, with constraints on the choice of 2G and 3G technology they can deploy. As in most other parts of the world, demand for data services has grown exponentially which risks outpacing the capacity of today's networks.

China Mobile continues serve the largest number of mobile users in the world (683 million customers at end June 2012) and faces increasing burdens on its data services. It's been unable to switch this data traffic to 3G because it uses the Chinese TD-SCMA 3G technology rather than the global 3G WCDMA widely adopted elsewhere. By June 2012, it only had 61.9 million 3G subscribers – less than 10% of its total – despite heroic efforts to build out network capacity and promote the technology.

The lack of a compatible Apple 3G iPhone is perhaps the most visible limitation – it drops back to 2G GPRS or needs to be used in a Wi-Fi zone instead. There are many good 3G TD-SCDMA smartphones on the market today – the choice includes models from Samsung and HTC in addition to Chinese vendors.

Competitors China Unicom and China Telecom have been capitalizing on their technology advantage. Their WCMDA and CDMA networks are compatible with the latest iPhone, allowing them to add 3G subscribers at a faster rate. China Unicom had 57 million 3G subscribers at the end of June 2012 and is catching up with China Mobile, despite having a much lower total installed base of 219 million. China Telecom, coming from a fixed network background, has built up a creditable 151 million subscribers, of which 51 million are 3G.

Data traffic is straining network capacity

The move to smartphones and data services has led to substantial data demand on China Mobile's 2G GSM network. It is recognized that increasing the macro network capacity alone cannot solve the problem. The GSM network of China Mobile still carries the majority of data service and now is overloaded. Large numbers of Wi-Fi hotspots have been rolled out with a stated target of 1 million by end 2013. These are accessible to all China Mobile subscribers with data usage counted against subscribers' data plans. China Mobile is part of the Wireless Broadband Alliance group, developing seamless interworking with Wi-Fi by using the phone's SIM card to authenticate and sign-on without needing to enter a username/password.

To solve the forecast data capacity demand, China Mobile plans to develop GSM/TD-SCDMA/TD-LTE/WLAN in parallel. Significantly, China Mobile accepts the concept that small cells could be more important than macrocells in the future Het-Network architecture.

China Mobile's progress in Small Cell technology

2008, China Mobile started to study femtocell technology and protocols.

Oct 2009, China Mobile announced plans to promote the femtocell to solve in-door coverage problem.

Oct 2010, China Mobile started trials of TD-SCDMA femtocell. Interworking between femtocells and the core network was tested and completed. Pre-commercial testing started with several friendly users.

Jan 2012, Suzhou started the official commercial deployment of TD-SCDMA femtocell aimed to home users, under the brand H-Zone.

During the development project, China Mobile applied for six patents. Early results are very positive - on-site testing showed the communication quality of a femtocell to be at the same level of a macro cell.

Suzhou, chosen as the technology trial city for TD-SCDMA femtocells, now has more than 10,000 TD-SCDMA femto users. The brand "H-Zone" (meaning Home Zone) is well understood and has been accepted by end users.

The CEO of Suzhou China Mobile was quoted as saying, "TD-SCDMA femtocell is not only building a new type of network, but also investigating a new commercial mode. Femtocell is not only to extend the signal, but also to build a suitable home environment for wireless broadband. We hope femto can be a strong force to offload the data. But current Femtocell Access Points have low capacity. So it can only be used in home and SOHO. In the future, the TD-SCDMA femto products must increase their capacity in order to be deployed in enterprise. TD-LTE is on the way, the experience of TD-SCDMA femto can be re-used in the LTE era. Most importantly, to realize the in-depth merge with WLAN is in the future roadmap of China Mobile."

In our recent interview with Doug Pulley of Mindspeed, we clarified that there are some eight or so vendors of TD-SCDMA femtocells/small cells today. The vast majority of these are basing their designs on the Mindspeed (formerly Picochip) chipset/reference design. The leading TD-SCDMA small cell vendors are said to be Femtel, Bravotech and Comba – all Chinese companies. Femtel is reported to be collaborating with Taiwanese ODM SerComm, who are very active in 3G femtocells and small cells worldwide.

China Unicom has its own 3G femtocell brand

China Unicom launched a femtocell service under the "3G Inn" brand in northern regions during November 2009. Huawei was the main vendor. There has been little public reporting of it that I can find, but numbers in the order of 20-30,000 femtocells, mainly used in Enterprise, are thought to be deployed.

Summary

These statements and trends reflect what we have seen elsewhere in the world:

• Small cells are an essential part of the data capacity and coverage solution, because macrocells won't solve the problem on their own
• A mix of 3G/4G and Wi-Fi radio technologies will all be used, with closer integration than today.
• Demand exists for higher capacity small cells, especially for enterprise and metrocell environments, where the low power/low capacity designs suitable for residential purposes aren't suitable.

My thanks to Calvin Wang of FemtoChina.com for providing much of the content for this article.