Are LTE smartphones not moving as fast as the networks they support?
Editor’s Note: In the Analyst Angle section, we’ve collected a group of the industry’s leading analysts to give their outlook on the hot topics in the wireless industry.
As mobile operator CTOs are rapidly migrating their networks to LTE-Advanced and LTE-Advanced Pro networks, device procurement managers should imminently put more pressure on device manufacturers and chipset suppliers to bring higher-category LTE modems faster to the market; otherwise, they could compromise the overall yield of their network. Mobile devices supporting LTE-A networks have now become common in the premium-tier segment and are increasingly reaching into lower tiers, with almost one in every four smartphones shipped in 2016 expected to be powered by a modem supporting a downlink speed up to 300 megabits per second.
Now that LTE-A networks are maturing, the industry is getting excited about the prospects of LTE-A Pro, notably the use of higher carrier aggregation combinations exceeding three channels, the use of advanced multiple-input/multiple-output antenna features and elevation beamforming, as well as the deployment of higher modulation methods such as 256 quadrature amplitude modulation. The combination of these technologies will enable the creation of gigabit-class LTE networks and devices.
LTE-A Pro is the next wave, but where are compatible smartphones?
Ninety of the 166 operators already deploying LTE-A networks have committed to deploying LTE-A Pro commercial services by 2017. Devices supporting these networks will be powered by modems with several user equipment categories, from Category 11 supporting up to 600 Mbps to Category 16 supporting up to one gigabit per second for downlink speeds. Although Category 11/12 modems are starting to be available in premium-tier devices from the likes of Samsung, LG and ZTE, the first Category 16 modem, the Qualcomm Snapdragon X16 LTE modem, was launched only in 2016, and early devices are not expected before 2017. The first gigabit-class LTE service will come from the Australian operator Telstra, initially supported by a NetGear MR1100 mobile router, which is powered by the Snapdragon X16 LTE modem.
These devices will be instrumental in improving the overall mobile service experience because they will enable users to stream and download richer content at faster speeds. Most importantly, these types of modems will greatly contribute to improving the overall network efficiency compared to Category 6 or even Category 9 modems, which could drastically limit spectrum utilization of LTE-A Pro networks in crowded hot spots where high-bandwidth services are utilized. ABI Research expects shipments of mobile devices powered by Category 11 or higher generations to jump from as little as 2% of total LTE devices sold in 2016, to exceed 36% in 2021.
Devices with superior LTE modems are essential for the success of LTE networks
Operators have a vested interest in linking and aligning their network investments with their device procurement strategy – otherwise they could degrade the overall service experience over their newly built networks. Operators are spending billions of dollars in improving the capacity and latency of their network highways by deploying LTE-A Pro. Yet a significant number of mobile devices using these networks are still powered by modems with relatively low-power engines, namely Category 4, Category 6 and to a certain extent Category 9 modems.
Assuming user behavior remains fairly similar as available network speeds increase, lower-category modems are likely to spend more time occupying network resources compared with faster modems. As such, this creates inefficient network utilization patterns that may congest even the most advanced LTE networks at peak times in dense urban environments. The effect perceived by the end user may be lower average speeds and even packet/call loss when the base station needs to schedule a high number of users at a busy hour. The situation exacerbates when the network is predominantly occupied by users with lower-category modems.
To illustrate the effect of higher-category modems, let’s assume a hypothetical and theoretical scenario where a gigabit-class LTE base station sector is streaming 12 megabytes of a very popular clip to its connected users simultaneously. The device category has a detrimental effect on network utilization.
If users are equipped with a Category 16 (1 Gbps LTE for downlink) modem, then the network can deliver the clip to approximately 10 users every second. Every user with a Category 16 device would occupy the network for a few milliseconds.
If users are equipped with a Category 4 (less than 150 Mbps for downlink) modem, the network can deliver the clip to a single user every second. In other words, every user with a Category 4 device would occupy the network for about one second.
The difference in the above figures may not appear as dramatic, but it does create a significant distortion when calculating for hundreds of users. For example, it will take 300 users with Category 16 devices approximately 30 seconds to stream the same clip, while it would take Category 4 users more than five minutes to do the same.
There are several added benefits to choosing a higher category device:
• Spectrum resources are free for more time, allowing the base station scheduler to allocate these more efficiently.
• The overall efficiency of the system is higher and the network can better decide how to allocate resources more efficiently.
• Higher perceived speeds at the device create usage elasticity, leading to the consumption of more data.
Device procurement managers should put the use of faster modems such as Category 11 and above very high in their priority specifications to OEMs and chipset suppliers. Failing to do this could have some dramatic consequences on network efficiency and could significantly compromise the overall mobile broadband experience even for premium subscribers using faster modems.
Modem designers and OEMs make trade-off decisions when adding high-performance modems. It takes a lot of effort, ingenuity and “know how” to design a high-performance modem chipset. If operators don’t choose wisely (the right device with the right modem in anticipation of the network environment it will support), then they could compromise their network capacity, spectral efficiency and service performance. In these conditions, the subscriber will likely blame the operator, the smartphone brand or both. When networks get congested, smartphones with poorly designed modems could bring unexpected costs to network capacity, spectral efficiency and the overall user experience.
