Mobile data consumption continues to grow at an incredible rate. According to Cisco's most recent Visual Networking Index (VNI), mobile data traffic will increase 13-fold between now and 2017. Mobile operators, whose existing networks and wireless spectrum resources cannot keep up with rising customer demand, are finding this rapid growth an enormous challenge.
To address this issue, the mobile industry is turning to the increasingly popular option of small cell technology. For those not familiar with the term small cell, small cell is what the term literally means – small cellular base stations that can be easily mounted on a pole or on the roof of a stadium as an example. Ever since Sprint deployed the first small cell (femtocell) in 2007, small cells have come a long way. As per Information, the number of small cells deployed globally reached 6 million in Nov 2012 surpassing the 5.9 million macro base stations in use for the first time. But the small cells of the future will likely differ from those available today in one key way. Currently, nearly all small cells support only one wireless technology — usually either 3G or 4G LTE. The next generation of small cells will feature multiple technologies, which will provide additional benefits for both carriers and end users. Designs in the pipeline for these multi-technology small cells include small cells that will combine 3G with Wi-Fi connectivity, or 4G with Wi-Fi, or even both 3G and 4G with Wi-Fi. I believe that Wi-Fi-capable multi-technology small cells will be the norm of the future since Wi-Fi operates on free, unlicensed frequency and could relieve much of the burden on the stressed cellular networks, leading to lower costs and improved user satisfaction.
However, there are challenges to overcome before vendors can bring such products to market:
- Product design: Since there are so many product variants that serve different purposes, with multiple frequencies and price points, equipment vendors must consider several factors to come up with a small-cell solution that will offer the best combination of price and performance.
- Multilayer management: Since operators deploy small cells along with their macro stations, they end up with heterogeneous networks, also called HetNets that pose significant management challenges. Equipment vendors must find ways to deal with the interference that is a result of several small cells being deployed near each other, along with their macro stations. Additionally, operators must develop a system to coordinate traffic between macro stations and small cells, and here I think advanced SON technology will be of help. Finally, this technology will require effective power management capabilities. All these management capabilities must be integrated into the software that runs the small cells.
Operational issues: Unlike macro base stations, where mobile operators control the physical site and can perform maintenance as needed, the sheer number and spread of small cells gives rise to maintenance challenges. Hence, operators will have to devise new ways to reduce both capex and opex. Here again, I think advanced SON techniques will help networks optimize traffic. I also think shared infrastructure models for small cell deployment will become popular.
Backhaul:Although operators will likely use their existing fiber or otherexisting backhaul infrastructure, this may not be sufficient. Hence I think a new approach may be necessary — such as solutions that incorporate different backhaul mechanisms, like line-of-sight or non-line-of-site microwave, millimeter wave, 5 GHz Wi-Fi, FTTx or VDSL2. Depending on the deployment scenario, it may be more cost effective to have the backhaul integrated into the small-cell product.
In spite of these challenges, multi-technology small cells represent an important opportunity for the mobile industry. I recommend that equipment vendors seek out partners who can help them navigate through the myriad possible product variants to find those that will offer the best price-performance ratio. In particular, they should seek out a scalable software solution that can serve in multiple products, so that they don't have to invest in new software for every different small-cell product they design. Our LTE small cell solution that we demonstrated recently in the 2013 Mobile World Congress Barcelona and received very encouraging feedback was conceptualized about a year back with this scalable architecture in mind. In addition, equipment vendors should partner with an integrated solution provider —one who can optimally integrate hardware, software, RF and mechanical design. Plus, their designs will need to be flexible and based on a plug-and-play architecture so that they can add capabilities as necessary for different operators and different locations. I also recommend that equipment vendors begin working on the next generation of multi-technology small cells today, if they wish to compete in a market that is poised for rapid takeoff.