I just returned from the Mobile World Congress (MWC) in Barcelona. The weather was chilly but the city welcomed us with warm hearts. This was a perfect place to experience the dramatic impact analog integration has on our mobile world. Thought I'd share some of my observations.
The MWC buzz around new smartphones and tablets is how these mobile devices have become an extension of our individual personality and behavior. More human interface features are being integrated (i.e., analog functions), such as vivid, high-sensitivity touch screens; gesture recognition; advanced audio processing; IR-based remote control; and 3D motion sensing. To handle all the data processing, almost every new device features more powerful quad-core processors.
These features, combined with the trend toward larger batteries and the fact that device form factors aren't changing, means that with each smartphone generation, device makers must add more stuff in the same size box. And this means that more analog integration is needed to solve some very difficult engineering problems. We're talking about high-efficiency power conversion that reduces heat dissipation and extends battery runtime; accurate fuel gauging and rapid charging to optimize battery life; high-performance sound processing with echo cancellation and noise suppression to deliver an exciting audio experience; and intelligent light sensing with high-sensitivity signal conversion to enable smart power-saving gesture recognition.
There was also a tremendous amount of talk and excitement about small cell base stations and Heterogeneous Networks (HetNet). To deliver the 4G experience that we all desire, we need a mobile infrastructure in place that's capable of delivering broadband services with ubiquitous connectivity. A HetNet architecture is needed to address the 4G explosion in both number of new subscribers and demand for data throughput. To do this, the mobile operators will deploy a HetNet made up of small cell base stations to complement the Macro Cell base station footprint (the large towers).
Its important to know that indoor usage is responsible for 80 percent of all mobile voice and data traffic. And that poor indoor coverage is a major reason for subscriber churn. To improve indoor coverage and deliver high data throughput on 4G networks the base stations are moving closer to mobile users. This is basically driven by Shannon;s Limit which sets the boundary for signal-to-noise ratio and information capacity in a given channel bandwidth. One way to improve communication link signal-to-noise ratio and overcome interference from buildings and walls is to move base stations indoors.
The role of RF analog integration in small cell base stations is astounding. And RF design is the quintessence of analog design, because it demands multi-disciplinary analog design talent. These small base stations use high-performance RF transceivers that integrate every analog function needed in the radio signal chain, except RF power amplifier and band selectivity filters. For example, a device introduced by my employer integrates a 2×2 MIMO radio, which means it has two RF receiver and two RF transmitter paths in a single device.
The device also integrates an incredible number of complex analog and mixed-signal blocks, including multiple fractional-n PLL/VCO synthesizers for local oscillator tuning across 700MHz to 2.7GHz range; high-speed ADCs and high-speed DACs used to quantize and synthesize wideband I/Q signals; multiple banks of RF mixers, low-noise amps and variable gain amps in the RF signal path; as well as digital decimation, interpolation, and channel selection filters. All in a single device — now this is analog integration!
It's obvious that analog integration is playing a critical and central role in the mobile industry — from new generation smartphones and tablets to a new generation cellular network infrastructure.