As wireless networks evolve, consumers continue to expect more from their mobile service – particularly faster data speeds and better performance. But each successive generation of wireless network has failed to solve the problems that vex carriers and consumers: slower-than-promised data speeds, short battery life, mobile devices that are too hot to handle, and generally poor performance. Now, as 4G becomes more ubiquitous, we wonder, are we doomed to repeat mobile history?
Wireless standards have been improved to enable networks to accommodate more users and faster data transmission. As the wireless industry shifted from 2G to 3G just a few years ago, standards such as HSPA+ were introduced to increase data capacity and double uplink speeds in order to accommodate the ever-increasing demand for mobile high-speed data services. Fast forward to today. The industry is going through a similar evolution to 4G, relying widely on the LTE standard to meet the need for even greater capacity and speed.
As these new standards are adopted, wireless signals become more complex. These complex signals require more radio transmit power for increased data rates on the same networks. But the power amplifiers in these 4G devices simply cannot efficiently produce the extra power needed while maintaining signal quality. As a result, data speeds suffer, batteries drain faster, and there is continued poor performance and consumer dissatisfaction.
So, what is the industry doing to end this vicious cycle? In a race to uncover an effective solution that is not cost-prohibitive, wireless carriers and mobile device designers are exploring a variety of approaches that could improve high-speed data and device performance while minimizing battery drain. Here are the methods that the industry is employing in an effort to bring consumers a better wireless experience:
Increase the density of towers – As mobile devices move further away from the tower, they need more power to communicate. By adding more towers, carriers can reduce the distance between consumers and towers. This solution presents many challenges: The expense of building and maintaining towers; objections by residents who do not want towers in their backyards; and governmental, legal, or bureaucratic issues related to permitting and potentially putting cells on buildings, water towers, and other tall structures, to name a few.
Increase downlink transmission power – Wireless carriers can boost the power output from the cell tower to the wireless device, which will help speed data downstream to the consumer. While this is a relatively simple fix from the carrier’s perspective, it is not a panacea for the host of issues that consumers experience as they seek to take full advantage of all LTE can offer. For example, this solution does not help address the power consumed and speed with which it takes to upload videos from their phones or tablets, or send large files and pictures to friends.
Greater reliance on WiFi and femtocells – Whether it’s the local Starbucks, the office WiFi network, or personally owned radio cells, consumers can connect to these local networks to help extend their battery life and improve high-speed wireless data performance because wireless devices do not have to work as hard to make a connection. But while these hot spots offer relief to capacity issues, they are not ubiquitous. Once the wireless device leaves the local hot spot and is forced to go onto the cellular network, these benefits disappear as well.
Increase transmit power produced by wireless devices – Today’s power amplifiers (PAs) cannot reliably produce the power required to enable LTE to reach its full potential. 4G/LTE signals have higher peak-to-average ratios and contain more information in the same bandwidth, which makes it harder for PAs to output signals at high transmit power without distortion, overheating, or excessive battery use. Some designers are relying on larger PAs to help wireless devices manage high-speed data – but because these PAs are less efficient for voice, this solution can cause even faster battery drain or greater heat build-up. Another approach to improve PA efficiency is through envelope tracking (ET), a technology that constantly adjusts PA voltage to ensure that it is operating at peak efficiency for the application being used. (Disclosure: My company makes ET power supplies.) ET enables voltage to be applied in real-time, adjusting instantaneously to input RF signal, which results in increased output power and capacity for high-speed data, faster upload speeds, and longer battery life. ET technology addresses LTE network capacity and speed issues in a more cost-effective way than attempting to build new cell sites or rely on consumer use of femtocells and WiFi networks to relieve capacity issues locally.
Wireless carriers have a myriad of technical approaches available to improve the consumer experience with high-speed wireless data. As the wireless industry prepares for more ubiquitous 4G coverage, it does not have to be doomed to repeat history. While some of the solutions may not be completely viable for political, financial, or practical reasons, high-speed data performance can be improved in both the network and the mobile device, enabling consumers to achieve the full promise of 4G.
Vikas Vinayak is CEO of Quantance Inc., a maker of ultra-fast, 4G/LTE envelope tracking (ET) power supplies that he co-founded in 2006 and that won both the Judge’s Choice and Audience Choice awards at GigaOm’s 2011 Mobilize LaunchPad conference. Throughout his career, Vinayak has been actively involved in the design of a wide variety of products, software, systems and circuits for the wireless communications and cable TV industries, and he holds several patents in RF technology and power management.
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