Reader Forum: Backhaul to the future

Editor’s Note: Welcome to our weekly Reader Forum section. In an attempt to broaden our interaction with our readers we have created this forum for those with something meaningful to say to the wireless industry. We want to keep this as open as possible, but maintain some editorial control so as to keep it free of commercials or attacks. Please send along submissions for this section to our editors at: dmeyer@ardenmedia.com or tford@ardenmedia.com.
There’s a great deal of discussion taking place amongst the “great and good” of the global mobile industry about coping with the exponential rise in demand for data services. It isn’t going to stop soon either – Google Inc. CEO, Eric Schmidt, said recently that his company is activating 160,000 mobile phones a day; Apple Inc.’s iPhone 4 has just launched and a whole new class of mobile data enabled consumer devices (touch-screen tablets) promises to add significantly to the load. The iPad is just the start.
Smart phones and tablets are unlike other data enabled mobile devices. Until relatively recently the data capabilities of your average phone were used only occasionally but these new devices positively encourage daily, or even hourly consumption of multiple megabits of data. It’s no surprise then that AT&T Mobility in the U.S. and O2 in the U.K. have thrown in the towel and abandoned their unlimited data packages and are capping use. Their networks simply can’t cope with the demand.
This is good news for the femtocell and Wi-Fi sectors since, if the network can’t cope, it looks very attractive to offload the data by hooking into the user’s fixed broadband connection. But this certainly isn’t a complete solution and it doesn’t address data use outside of the home (we are talking about mobile devices after all). The painful truth is that mobile network operators are facing a monumental upgrade issue, both for the radio access and backhaul components.
Around the world we can expect to see a great many upgrades of existing cell sites and a rapid increase in their total number. The capital and operational investment is unavoidable and the industry will have to carefully consider the environmental impact.
That leaves the backhaul component, and here the industry has new options in the form of next generation point-to-multipoint microwave. The acronym PMP, has been seen before, particularly in the U.S. market where it was associated with local multipoint distribution service, a 1990s solution for delivering “last mile” wireless broadband access as an alternative to a cable or ADSL connection.
Next generation PMP is a relatively new transmission technology, designed specifically for mobile backhaul, providing 150 megabits per second cell site capacity. It is now being adopted with some enthusiasm around the world. That is particularly true in developing markets where operators are much more likely to consider new technologies. They are unencumbered by legacy network equipment and their design methodology and working practices aren’t as established – choosing the same old technology because “that’s what we’ve always used” isn’t an option. The result of this new approach to backhaul is that PMP microwave now supports, for instance, the world’s busiest HSPA network (in the Middle East) and one of the world’s first and largest all-IP networks (Africa).
Unlike legacy point-to-point microwave technology, PMP uses a fundamentally different architecture. Instead of the simple one-to-one relationship inherent in PtP networks, it utilises a “broadcast” format to link a single hub to multiple cell sites and intelligently shares and manages the available capacity. Roughly half the number of radios are required.
The net outcome is much greater capacity, less complexity, rapid installation and deployment and as a result, an approximate 50% saving in both capital and operational expenditure. Furthermore the effect on the environment, measured in terms of visual impact, production and maintenance resources and energy savings, is considerable.
These factors have driven the adoption of PMP in developing markets but the data crunch means operators in developed markets are now facing similar issues and the traditional options aren’t providing the answers. Optical fibre might seem the obvious solution. It provides almost limitless capacity, but in most instances the capital and environmental impacts aren’t worth thinking about, particularly in the current climate. Traditional PtP microwave is old technology and is heavy on capex but also on opex. It is resource hungry and the constraints of the architecture waste spectrum resources and limit throughput. PMP now offers developed market operators the ideal balance between capital and operating expenditure and goes a long way to addressing the environmental impact of the expected growth in cell sites and hubs.
It is new technologies that are driving the demand for data amongst mobile users and it is new technologies that need to be adopted to meet the demand. Femtocell and Wi-Fi offload will continue to be adopted but the core network, and the backhaul network in particular, needs the same innovative approach.