Tracking upload speeds in Spain

When it comes to the direction of mobile data, we're becoming a much more symmetrical society. We're not just surfing the internet and downloading video, we're creating content and streaming video from our phones. That means upload speed is becoming increasingly important when it comes to measuring the consumer mobile data experience.

We'll soon be including our upload metrics among our key awards categories in our State of Mobile Networks reports, but first we would like to take the opportunity to examine some of the interesting trends we see with upload in a few key countries, starting with Spain. The Iberian country already has high expectations for mobile performance. As our last Mobile Networks Update on Spain shows, Spaniards already see very fast 4G download speeds and have a high level of 4G access. Consumers there expect to see good quality download and streaming experiences, and they expect that kind of quality experience often. Those same consumers are likely to hold those same high expectations for upload. So let's take a look at our 4G upload speed measurements for Spain's four nationwide operators, which were collected between Sept. 1 and Nov. 1 (the same test period as our last Spain report).

The first thing you'll notice is that 4G upload speeds are much slower than 4G download speeds. In the Spain report, our average LTE download measurements ranged from 25.6 Mbps (Yoigo) to 35.3 Mbps (Vodafone). For upload, we get not only much slower speeds, but also much narrower range of speeds. That's not a failure by any of Spain's operators; rather it's a function of cellular technology. The downlink in cellular networks is always much more powerful than the uplink. It's easy to see why when you consider the source of each transmission. The downlink is generated by massive antenna at a cell site with its own industrial power supply. Meanwhile, the uplink is generated by your phone with its tiny little antenna and a power supply the size of chocolate bar.

Second, you'll notice that the operators’ rankings for 4G upload speed almost directly mirror our rankings for 4G download speed. Vodafone had the fastest 4G upload in our tests at 12.7 Mbps, while Movistar came in second with an upload of 11.9 Mbps. Orange and Yoigo were very close in this metric, resulting in a statistical tie for 3rd place. Again, there are no surprises here. Download strength and upload strength often go hand in hand. Most LTE networks are what are known as split-spectrum technologies. That means the uplink and downlink use separate frequency bands of equal size. Consequently if an operator were to increase its speed by adding downlink capacity, LTE technology would normally dictate an proportional capacity increase on the uplink side.

But there are always exceptions to the rule, and as 4G technology evolves those exceptions will become much more common. We see many operators augment their networks (Vodafone Spain among them) with an alternate form of LTE technology, called TD-LTE, that allows them to vary the amount of spectrum allocated to downlink and uplink. Also many operators have started testing out supplementary downlink technologies, which focus on bulking up download speeds without adding similar heft to the upload side of their networks. In short, soon the upload/download picture could no longer be so black and white. Operators could start tweaking their networks to differentiate their 4G services in terms of upload. Given that trend, as well as the shift from content consumption to content creation in mobile, it's an ideal time for us to start tracking upload speeds. Be sure to check this blog regularly as we'll be exploring the upload dynamics in other countries.