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Making Your Wireless Network Adaptable to Changing Service Needs

Constructed during World War II, Maginot Line cost 5 billion francs (around USD 35 billion). It was composed of multiple facilities such as artillery, trenches, fortresses, kitchens, power stations, hospitals, and factories, and tram channels were constructed in large defense works. At the time, the French regarded the line as indestructible. Unexpectedly, the Maginot Line was broken through by the German army in less than one month. Similar to the Maginot Line, there were also other ‘indestructible’ defensive lines during World War II. For example, the German’s Atlantic Wall and the Gin Drinkers Line. These defensive lines were all broken through in less than one month. Builders of these defensive lines attempted to rely on fixed defensive lines to defend against invasions. However, in dealing with dynamic situations, these defensive lines could hardly provide effective defensive capabilities. To put it differently, once the actual situation differs from the expected situation, these defensive lines will lose the effective defense capabilities. From these events, it is clear that flexibility and on-demand resource allocation are of vital importance in all strategic situations.

Wi-Fi Constructor: Faced with Network Planning Problems

Attack and defense strategies born in wars can be applied with a wider scope, such as Wi-Fi network construction and planning in the wireless communications field. Most Wi-Fi network build outs may not realize that they are similar to the Marshals of France under the threat of Germany seventy years ago. Similarly, Wi-Fi network build outs need to think how to arrange and manage their resources. In the wireless network field, constructors need to make quick and accurate judgment calls regarding network planning and service models.

In wireless network planning, network constructors need to determine high-traffic areas, areas allowing access for multiple services such as voice and video services, and common data areas. Based on their judgment, network constructors determine the types and quantities of Access Points (APs). This process is similar to the military strategy of dividing the entire coverage area into main defense areas, moderate defense areas, and general defense areas.

From an initial perspective, things will go as per plan if the actual user traffic and service model developed as expected. However, once the environment and services change, a more flexible and elastic mechanism is needed.

Two years ago, wireless networks were merely used to replace wired networks in order to provide similar access performance. As mobility changes office modes and service procedure, wireless networks must adapt to changing needs.

Similar problems frequently occur in enterprises. For example, wireless resources in the meeting room are easily exhausted because the number of participants in a temporary meeting exceeds the usual limit. A marketing department which has high network requirements moves to another area allocated with lower network priority, disturbing the enterprise’s network settings. Usually, enterprises do not have the time or funds to resolve these problems once these problems are encountered.

To effectively solve the problems, Wi-Fi networks at the access layer need to be elastic. When user traffic surges, network capacity can be flexibly expanded as required. However, current wireless networks can hardly provide elastic performance.

Issue: RF Combination Remains Unchanged for over Ten Years

It has been 13 years since the IEEE 802.11g standard was approved in 2003. During the 13 years, Wi-Fi technologies, APs, and terminals have been rapidly developing. Thanks to the higher bandwidth provided by the 5 GHz frequency band, the forwarding rate offered by an AP increases from 54 Mbit/s to 1.3 Gbit/s. This is about a 25-fold increase. With the decrease of chip price, terminals now support both 2.4 GHz and 5 GHz frequency bands rather than the single 2.4 GHz frequency band. 5 GHz frequency band can provide higher user capacity and bandwidth with less interference.

Figure 1

As the installed base of 2.4 GHz terminals is large, the Radio Frequency (RF) combination of ‘2.4 GHz + 5 GHz’ has remained unchanged for over ten years. If more 5 GHz frequency bands are required to increase the network capacity, customers have to add APs and disable some 2.4 GHz frequency bands. This wastes about 50% of investment.

Obviously, wireless networks are in dire need of change. RF combination is the first change to be affected.

SDR: Makes a Wireless Network Adaptable to Changing Needs

In 2014, Huawei developed the Software-Defined Radio (SDR) solution targeting the stadium scenario. In addition to 2.4 GHz and 5 GHz frequency bands, the solution supports software-defined policies. In brief, the RF combination can be shifted to ‘5 GHz + 5 GHz.’ All APs can work on the 5 GHz frequency band which provides more clean wireless environment, more available channels, and higher forwarding rate. This combination improves the access bandwidth to 2.6 Gbit/s. Compared with the traditional fixed combination of ‘2.4 GHz + 5 GHz,’ the new combination improves 50% of throughput and increases 40% of the number of allowed access users.

Dual-5G mode will force the abandonment of the 2.4 GHz frequency band. In 2016, Huawei has upgraded the SDR solution to SDR2.0, which can be applied to the triple-radio AP4030TN. The AP4030TN supports three RF combinations:

  • 2.4 GHz + 2.4 GHz + 5 GHz (applicable to the Internet of Things scenario)
  • 2.4 GHz + 5 GHz + 5 GHz
  • 5 GHz + 5 GHz + 5 GHz

Administrators can flexibly choose a RF combination. A single AP can support the concurrent access of 100 users and provide 4 Mbit/s bandwidth for each user.

Figure 2. Huawei AP4030TN Supports Three RF Combinations

In addition to defining the new RF combinations, SDR can define the RF to work in the monitoring mode in wireless positioning solutions. The RF environment then can be dynamically detected, providing real-time data for radio calibration, and improving the precision of wireless location to 3 meters.

The recently popular Network Functions Virtualization (NFV) transforms dedicated hardware to general hardware in order to re-define the network resource allocation mode. Like NFV, SDR re-defines the wireless resource allocation mode, shifting the static mode to dynamic mode.

By Chen Siyuan