Issues Facing Cellular Networks

Cell-TowerMost networks today are under stress due to growing broadband traffic. The networks that are easily the most stressed are cellular networks and I think that there can be lessons learned in looking how mobile providers are struggling to keep up with demand. Consider the following current issues faced by cellular network owners:

Traffic Volume Growth. Around the world cellular networks are seeing between 60% to 120% annual growth in data volumes. The problem with that kind of growth is that as soon as any upgrade is made to a part of the network it is consumed by the growth. This kind of growth means constant choke points in the network and problems encountered by customers.

The large cellular companies like Verizon and AT&T are handling this with big annual capital budgets for network improvements. But they will be the first to tell you that even with those expenditures they are only putting band-aids on the problem and are not able to get ahead of the demand curve.

WiFi Offload Not Effective. For years cellular networks have talked about offloading data to WiFi. But the industry estimates are that only between 5% and 15% of data through cellphones is being handled by WiFi. This figure does not include usage in homes and offices where the phone user elects to use their own local network, but rather is the traffic that is offloaded when users are outside of their base environment. Finding ways to increasing WiFi offload would lower the pressure on mobile networks.

Traffic has Moved Indoors. An astounding 75% of mobile network traffic originates from inside buildings. Historically mobile traffic came predominantly from automobiles and people outside, but the move indoors looks like a permanent new phenomenon driven by video and data usage.

The biggest impact of this shift is that most cellular networks were designed and the towers spaced for outdoor customers and so the towers and radios are in the wrong places to best serve where the volume is greatest today. This trend is the number one driver of micro cell sites that are aimed at relieving congestion for specific locations.

Network Problems Can be Extremely Local. The vagaries of wireless delivery mean that there can be network congestion at a location but no network issues as close as 50 yards away. This makes it very hard to diagnose and fix network issues. Problems can pop up and disappear quickly. A few more large data users than normal can temporarily cripple a given cell site.

Network owners are investigating technologies that will allow customers to pick up a more distant cell site when their closest one is full. Wireless networks have always allowed for this but it’s never worked very well in practice. The carriers are looking for a more dynamic process that will find he best way to serve each customer quickly in real time.

Networks are Operating too Many Technologies. It’s not unusual to find a given cell site operating several versions of 3G and 4G and sometimes still even 2G. The average cell site carries 2.2 different technologies, provided by 1.3 different vendors.

Cellular operators are working quickly towards software defined networks that will allow them to upgrade huge numbers of cell sites to a new version of software at the same time. They are also working to separate voice and data to different frequencies making it easier to handle each separately. Finally, the large cellular carriers are looking to develop and manufacture their own custom equipment to cut down on the number of vendors.

Still Too Many Failures. There are still a lot of dropped voice calls, and 80% of them are caused by mobility failures, meaning a failure of the network to handle a customer on the move. 50% of dropped data sessions are due to capacity issues.

Cellular providers are looking for the capacity to more dynamically assign radio resources on the fly at different times of the day. It’s been shown that there are software techniques that can optimize the local network and can reduce failures by as much as 25%.

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