HetNet: When Big Cells and Small Cells Collide

Market outlook and technology implications for HetNet

05/16/2011 | 21 pages
Price: $850.00

Even under the most optimistic set of assumptions, we demonstrate that by 2020 at least 25% of the mobile data traffic in North America will have to be offloaded from the traditional macro network. Similar results are likely in other markets. This result assumes that an additional 500MHz of new spectrum becomes available in the next several years. If we use assumptions that are more consistent with industry consensus (e.g., mobile data growth) then the percentage is substantially higher, to the point that it reaches nosebleed levels.

Further, the industry cannot afford to sit back and wait since in many scenarios there a double-digit percentage of the mobile data traffic must be offloaded as early as 2015. Something must be done in order to address this dramatic growth of mobile data traffic. Network optimization, advanced cellular technologies (e.g., LTE), and data compression algorithms help, but they may not be enough on their own. Instead, operators will need to offload capacity from their macrocells onto smaller cells. Enter HetNet.

In this issue of Signals Ahead we provide a detailed technical analysis of Heterogeneous Networks, including several ‘modeling perspectives” which demonstrate the clear need for macrocell capacity offload solutions. Specific topics include the following:

• The Outlook.We provide a series of analytical exercises, along with sound reasoning and sensitivity scenarios, which demonstrate the importance of macro network offload. We show, for example, that even under the most optimistic set of assumptions, including the availability of 500MHz of new spectrum in the coming years, at least 25% of the mobile traffic will have to be offloaded from the traditional macro network by 2020. Under most scenarios, the percentage is substantially higher. Further, with most studies a double-digit percentage is required as soon as 2015.
• The Definition.Most readers should understand the basic concept of HetNet, but for those readers who are still coming up to speed we provide a good primer.
• The Challenges. When small/low-power cells are deployed in a network consisting of large/high-power cells, problems inevitably occur. These new cells, after all, are nothing more than new sources of interference unless they are used effectively and efficiently. In some cases, in particular with pre-Release 10 devices, the mobile device may not even detect the presence of these new cells, thus defeating their intended purpose.
• The Solutions. The beauty of LTE is that it divides the data and traffic channels into discrete partitions in the frequency and time domains. This feature can be leveraged to minimize interference and to maximize the combination of macrocells, picocells, and eventually femtocells. New technology enablers, including ABS (Almost Blank Sub-frame) and advanced receiver architectures which support interference cancellation are only part of the story. We discuss.
• The Status. We discuss when HetNet will become a reality. Fortunately, it appears to be sooner rather than later.