More than 67,000 attendees from 205 countries recently descended on Barcelona to check out the latest innovations from more than 1400 exhibitors at Mobile World Congress (MWC) 2012. Despite these numbers, though, three processor issues rose above the event’s buzz: quad cores, high-resolution graphics, and voice quality and reliability.

To Quad Or Not To Quad

This year’s mobile market is shaping up as a battle between the quads and the quad-nots. We knew Nvidia would be first to ship a quad-core mobile processor. At this year’s MWC, the company debuted several phones and tablets based on its Tegra 3 chip. More surprising was Huawei’s announcement of its first-ever application-processor design, the quad-core K3V2. These vendors, along with Freescale and its i.MX 6Quad, are extolling the virtues of four CPU cores: higher peak performance and better performance per watt.

On the other side of the debate are Qualcomm, Texas Instruments, and Apple. These vendors are relying on dual-core processors for most or all of 2012, and they are getting a bit testy about the attention given to their upstart competitors. At its recent iPad introduction, Apple made a nearly unprecedented move, directly comparing its product against a competitor’s. Dogged by false rumors that it would jump on the quad-core bandwagon, Apple (rather unconvincingly) asserted that its new dual-core A5X will outperform the quad-core Tegra 3.

The quad-nots have some credibility. Not much mobile software is optimized to run on four CPUs. Most apps will use only one or two cores, accruing no advantage on a quad-core processor. The most important piece of software is the browser, which phone makers can rebuild themselves to run on four cores. Nvidia is also working with leading-edge game developers and already has several quad-optimized apps on Google Play. By the end of the year, plenty of quad-core software should be available. Of course, by the end of the year, more vendors will be shipping quad-core processors.

It is no coincidence that the three vendors with the most smart-phone processor share are sticking with proven dual-core technology. To get attention, the smaller, up-and-coming companies must innovate faster and even go out on a limb a bit. The quad-nots will spend the next several months denigrating quad-core technology—then suddenly begin singing its praises once they have their own quad-core products ready to ship.

Looking Good With Better Graphics

Apple’s new iPad highlights another trend: investing silicon in graphics instead of CPU performance. In its original A5 processor, used in the iPad 2 and iPhone 4S, Apple devoted 31 mm2 of die area to the graphics unit (GPU), delivering the largest and fastest GPU in any mobile processor. For the A5X, Apple doubled the size of this GPU, resulting in an expensive but incredibly powerful graphics processor. Its graphics performance delivers high-quality images even on the new high-resolution iPad screen.

With tablet screens moving beyond HD and even smart phones moving to 720p resolution, powerful graphics units are in demand. Furthermore, people are using their devices for more than just browsing. Smart phones are quickly replacing the Nintendo DS and Sony PSP as the handheld gaming platform of choice (witness the disappointing sales of the 3DS and Vita), and tablets are challenging the incumbent but aging console systems. Encouraged by Nvidia and others, developers are porting console-style games to Android and iOS.

Apple is not the only vendor to recognize this trend. At MWC, Qualcomm announced a new “Pro” version of its S4 processor. Its primary upgrade is a next-generation GPU that doubles the performance of its predecessor. Samsung is using the latest GPU from Imagination Technologies to soup up its newest application processor. Nvidia, a company that knows a thing or two about graphics, plans to focus on boosting GPU performance in its Tegra 4 processor, after innovating mainly in the CPU subsystem for Tegra 3.

The CPU determines what a mobile device can do, but the GPU determines how good it looks while doing it. Now that mobile processors can run a wide range of apps, system vendors are focusing more on looking good, even if it costs a little more. Successful chip vendors will support their customers’ needs with faster GPUs.

Can You Hear Me Now?

Even Sigmund Freud might admit that sometimes a phone is just a phone, even when it’s a smart phone. After browsing, gaming, and navigating to their heart’s content, people still make phone calls with their mobile phones. And when they do, more often than not, the quality of the voice call is poor.

Part of the problem is the inherent unreliability of mobile wireless signals, but part is also caused by the carriers’ use of aggressive digital compression. Compression allows carriers to squeeze more conversations into a given set of frequencies, avoiding costly network upgrades.

Two trends, however, could change this dynamic. First, carriers are upgrading their network anyway to increase data capacity, so greater voice capacity often comes for free. Second, as more people experience Skype and other high-quality audio services, they begin to expect more from their mobile phones.

Those of us who grew up with analog landlines are used to phone calls that cut off frequencies above 3.6 kHz. Most cellular networks use a similar (or lower) cutoff point. Skype, however, can transmit sounds up to 20 kHz, making conversations more natural sounding and easier to understand.

As carriers prepare to roll out high-quality audio (often with a surcharge), chipmakers are embedding support for these codecs into their processors. Because of the greater computation involved, these codecs may require hardware changes. Tensilica, for example, recently announced a new audio DSP core with 32-bit precision and 50% greater performance, enabling support for HD voice. Processor vendors can license this solution rather than implementing their own.

To further improve phone calls, mobile chipmakers are adding noise suppression. This technology, pioneered by a startup called Audience, reduces background noise while amplifying the speaker’s voice (see “Chip Reduces Background Noise In Cell-Phone Calls”). Apple has integrated the Audience technology into its A5 and A5X processors.

Qualcomm has developed a similar technology, which it calls Fluence, that has been deployed in HTC, Nokia, and Motorola phones. Noise suppression also improves the accuracy of voice-recognition software, such as Apple’s Siri. We expect it to become a standard feature in mobile processors.