Since the first mobile networks were deployed, user demand for Quality of Experience have driven infrastructure vendors, mobile network operators, and chipset and software technology providers to continuously evolve their ideas of what mobile networks should look like and how they should be configured.
As far back as 2001, call quality (call drops and call failures) was cited by consumers as a key driver of customer dissatisfaction and churn. More recently, Virgin Media surveyed consumers to determine what would convince them to switch mobile network operators.
Of those surveyed, 22% cited a more reliable data connection, while 34% cited better network coverage as reasons to switch operators. Whereas the network coverage issues are consistent with consumer behavior more than 10 years ago, the introduction of smartphones has increased value of data for end users.
These changes in the elements required to ensure a great overall Quality of Experience for consumers have brought a new vision of what a modern mobile network would look like. The toolbox of solutions available to mobile network operators have grown considerably over the last two to three years especially. Today, there is broad industry consensus that a Heterogeneous Network – or Het-Net – is the most sensible approach to addressing the needs of consumers.
Het-Nets are networks that utilize a variety of technologies and techniques to address the three core aspects of an end-user’s Quality of Experience in an integrated fashion. They are: coverage, network quality and throughput.
From an air interface perspective, the tools in the toolbox are HSPA, LTE and Wi-Fi. Each technology plays a critical role in providing the services demanded by consumers. Each of the air interfaces can be implemented and rolled out in a number of different configurations.
Traditionally, Macro Cells were used to provide coverage and capacity needs. As these needs changed, new macro cell configurations, such as 6-sector cells, were used instead. Over the last five years, we have also seen a big push towards the use of both outdoor and indoor small cells to complement the macro network.
The industry experience in rolling out small cells and the best practices to use are well captured in the Small Cell Forum’s release plan, the latest being Release 2.0 which focuses on Enterprise Small Cell deployments. Within this release plan, all the available tools in the operators’ toolbox, including technologies such as Smart Signal Boosters used in conjunction with small cells, are outlined.
One of the key technological advances that has made this migration from macro cell dominated networks to integrated Het-Nets possible is the deployment of Self-Organizing Network (SON) solutions. The basic value proposition of SON is simple – as the number of nodes in a network grows, it becomes extremely difficult to correctly configure and manage the network.
SON algorithms automate these tasks and ensure that the network is always performing at its peak. Virtually all Het-Net infrastructure nodes (macro cells, small cells, Wi-Fi enable small cells as well as Smart Signal Boosters) support SON algorithms, which has led to these technologies being widely deployed.
With wide deployment comes cost reductions fueled by the development of new components and technologies. First amongst equals in this area has been the development of multiple baseband processors to support the development of a variety of cost effective small cell solutions.
Companies such as Qualcomm, Broadcom, Intel (through its recent acquisition of the Mindspeed Wireless Group), Freescale and Cavium all offer a variety of small cell baseband processors that cater to designs ranging from the smallest Femtocells (used primarily in residential environments) to larger enterprise microcells capable of supporting in excess of 64 simultaneous users.
On the smart signal booster side, HetNet capability can be achieve through the use of architectures such as the multi-core ARES processor which features six 32-bit RISC cores providing the needed horsepower to support HSPA and LTE networks.
Key to the widespread deployment of this device is the inclusion of SON algorithms that allows the processor to automatically configure the smart signal booster to seamlessly interoperate with other small cell technologies as well as the macro network.
Together, traditional small cells as well as smart signal boosters can optimize the coverage and capacity needs of a network to ensure the best Quality of Experience for end users whilst reducing the overall cost of ownership of the network for the mobile operator.
Michiel Lotter has more than 16 years of experience in the field of wireless communication. He was a co-founder of Zyray Wireless, which was acquired by Broadcom. Following this he was a senior director responsible for platform development in Broadcom’s Mobile Communication business unit. Mr. Lotter also spent eight years with Alcatel Networks. He holds a Ph.D. from the University of Pretoria, and has authored and co-authored several journal and conference papers, as well as two books on wireless communications. He is the named inventor or co-inventor on 14 issued patents.