China Mobile Research Institute
1 Introduction
1.1 Background
Today‟s mobile operators are facing a strong competition environment. The cost to build,
operate and upgrade the Radio Access Network (RAN) is becoming more and more expensive
while the revenue is not growing at the same rate. The mobile internet traffic is surging, while
the ARPU is flat or even decreasing slowly, which impacts the ability to build out the networks
and offer services in a timely fashion.. To maintain profitability and growth, mobile operators
must find solutions to reduce cost as well as to provide better services to the customers.
On the other hand, the proliferation of mobile broadband internet also presents a unique
opportunity for developing an evolved network architecture that will enable new applications
and services, and become more energy efficient.
The RAN is the most important asset for mobile operators to provide high data rate, high
quality, and 24x7 services to mobile users. Traditional RAN architecture has the following
characteristics: first, each Base Station (BS) only connects to a fixed number of sector
antennas that cover a small area and only handle transmission/reception signals in its coverage
area; second, the system capacity is limited by interference, making it difficult to improve
spectrum capacity; and last but not least, BSs are built on proprietary platforms as a vertical
solution. These characteristics have resulted in many challenges. For example, the large
number of BSs requires corresponding initial investment, site support, site rental and
management support. Building more BS sites means increasing CAPEX and OPEX. Usually, BS‟s
utilization rate is low because the average network load is usually far lower than that in peak
load; while the BS‟ processing power can‟t be shared with other BSs. Isolated BSs prove costly
and difficult to improve spectrum capacity. Lastly, a proprietary platform means mobile
operators must manage multiple none-compatible platforms if service providers want to
purchase systems from multiple vendors. Causing operators to have more complex and costly
plan for network expansion and upgrading. To meet the fast increasing data services, mobile
operators need to upgrade their network frequently and operate multiple-standard network,
including GSM, WCDMA/TD-SCDMA and LTE. However, the proprietary platform means mobile
operators lack the flexibility in network upgrade, or the ability to add services beyond simple
upgrades.
In summary, traditional RAN will become far too expensive for mobile operators to keep
competitive in the future mobile internet world. It lacks the efficiency to support sophisticated
centralized interference management required by future heterogeneous networks, the flexibility
to migrate services to network edge for innovative applications and the ability to generate new
revenue from revenue from new services. Mobile operators are faced with the challenge of
architecting radio network that enable flexibility. In the following sections, we will explore ways
to address these challenges.
