Tantra Analyst

Differentiate 5G Smartphone Performance With The Right Modem And RF Strategy

A silver lining of the dark cloud of the pandemic is the realization of how important connectivity is for our lives. For this reason, I am very confident that the 5G freight train that might slow down in the short-term will pick up speed very quickly. So, once we are out of emergency mode, 5G smartphones will be well on their way to becoming mainstream. Then the question becomes, “How can OEMs differentiate themselves?” 5G connectivity performance will be one of the key differentiators, and an advanced modem integrated with an efficient RF system will be a key lever. Let’s explore how companies can employ this to compete and win.

What Does Connectivity Performance Mean?

Although connectivity significantly affects the real user experience, measuring the connectivity performance of phones has always been enigmatic even for so-called reviewers and influencers. For example, there are thousands of YouTube videos of people comparing camera performance, but hardly any testing connectivity. Even those are limited to simple speed test comparisons.

Connectivity performance can be measured on multiple vectors. For example, one can say that a certain phone has better performance than another if it has better coverage (signal strength) at the same distance from the base station; higher speed at the same signal strength; and uses lower power (longer battery life) for the same speed. Another important vector, form factor (thinner and lighter), is hard to measure as it is impacted by many other considerations than just connectivity. The modem and RF system combination of the phone directly impacts all these performance vectors, which, in turn, affects the actual experience of the users.

Components Of A Smartphone’s RF System

Today’s smartphones, especially the ones supporting 5G, include a long list of RF components. These include multiple power amplifiers (PA), low noise amplifiers (LNA), a bunch of filters and switches, and advanced components such as antenna tuners, envelope trackers and more. According to industry analyst firm Omdia, the bill of materials (BoM) of RF components constitutes a significant portion of modern 5G smartphones. That means the RF system is not only important from a performance and user experience point of view, but also from a financial perspective.

Differentiating Based On RF Performance

The impact of RF is even more pronounced in 5G than 4G, because of the advancements and complexities involved. There are mainly three approaches for implementing the RF system in a phone, which results in varying performance. Let’s look at them in the ascending order.

Discrete – Utilizing multi-vendor modem and RF components: This has been the traditional approach and involves the device OEMs doing the system design, working with the multiple modem and RF component suppliers and putting the phone together. This approach worked perfectly fine for 2G and 3G as the technology complexity was minimal and there were only a few spectrum bands to support and OEMs were technology developers themselves. With the advent of 4G LTE — especially with LTE Advanced and Gigabit LTE, where there were complex technologies such as MIMO, carrier aggregation, LAA (licensed assisted access) and others — RF systems got increasingly complex, requiring specialized skill sets and expertise. While this approach barely works for 4G, it is extremely hard for 5G sub-6GHz bands, but almost impossible for millimeter-wave (mmW) bands.

Integrated – A closely knit, integrated modem and RF system: This approach not only significantly simplifies designing and go-to-market process, but also substantially improves performance. The famed 5G’s speeds and capacity are because of complex features, such as beamforming and beam steering. They need extremely close-knit interaction between the modem and the RF system to work, which is only achievable through the integrated approach. As mentioned, RF needs a specialized skill set that can only come with sustained investment and development efforts. An integrated approach allows fine-tuning of both modem and RF systems as well as interworking to maximize performance.

Just to be clear, an integrated approach is not mandatory, but without it, performance will be below par.

Advanced – Integrated approach topped with advanced features: The third approach brings advanced features such as an antenna tuner (AT), envelope tracker (ET), power save (PS) and smart transmit (ST) that further enhance performance. AT allows the device to select and switch between multiple technologies (5G, 4G, Wi-Fi) and tens of bands and thousands of band combinations to maximize performance. ET closely manages the device’s transmit power so it transmits only the necessary amount. PS maximizes the device’s sleep cycle to lower power consumption. ST optimizes the device transmit duty cycle so the device can transmit at a higher power level while being within the maximum regulatory power envelope. AT and ET improve sustained speeds, coverage, and battery life and enable a smaller and thinner form factor. PS extends battery life and ST increases speed as well as coverage.

All of these features are applicable to Sub-6GHz bands, whereas only PS and ST are applicable to mmW bands for now.

Again, these features are optional but are potent tools for OEMs to offer superior connectivity performance and exceptional user experience so users get higher speeds, better coverage, and longer battery life.

Qualcomm’s Snapdragon X55 is a good example of commercial implementation of the advanced approach. (Full disclosure: Qualcomm is a client of mine.)

Once the dark cloud of the pandemic clears, 5G proliferation will continue, probably with much more vigor than before, and quickly make 5G mainstream. In such a competitive environment, 5G smartphone OEMs will have to compete on performance and user experience, among other things. A sound RF strategy utilizing the integrated modem and RF system approach with advanced features will allow them to offer superior performance and differentiate themselves.

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