The Charm of Personal Medical Electronics

Last week I attended the Medica right on my doorstep here in Düsseldorf. My goal was to investigate the state of mobile healthcare - mHealth - with a focus on personal medical electronics. We’ve seen lots of fitness devices becoming mainstream over the past years, but what about personal devices for those who have a chronic ailment? For the uninitiated: Medica is the world’s largest event in the medical sector and attracts over 130 000 visitors each year to see products and services from some 5000 exhibitors.

Photo courtesy of Messe Düsseldorf GmbH

Having steered well clear of pavilions covering surgical devices (not for the faint of heart), one thing that immediately caught my eye was the large number of country booths in each hall inhabited by many smaller companies with innovative products. After visiting around 10 of these, I was surprised to often find the conversation steering towards regulation, compliance and the lobbying power of large incumbents in the medical and pharmaceutical field. It quickly became clear that mHealth has an armoury of jaw dropping technology at its disposal to propel the industry forward, yet security, privacy concerns, slow regulation & legislation and the interests of industry heavyweights curb and constrain enthusiasm and progress in adopting new technologies. Mobile health (mHealth) technology circumvents the technical challenges of existing health systems and provides a more flexible way of enhancing patient self-care. mHealth ultimately equips the patient with completely new 24/7 self-monitoring capabilities that change the dynamics of the doctor-patient relationship.

A second observation from my visit was the number of “cloud based” solutions on offer. In particular for establishing new electronic medical record systems to receive and process information from mobile devices, moving them to “the cloud” so that physicians and other experts have “anytime” and “anywhere” access to a patient’s health status.

The smartphone is a welcome hub for many mHealth solutions. It records incoming data from specialized sensors monitoring a patient’s condition, and wirelessly moves this data to “the cloud”. Often the device’s display provides insightful visual feedback. If necessary, acoustic alarms or haptic prompts notify the patient to take a corresponding course of action.
On the sensor front there are a plethora of exciting solutions around, many if the form of “wearables” and some as “implants”. Two examples from my Medica visit, both from companies who license their technology, give an idea of what’s round the corner. The Israeli company Healthwatch Technologies showcased T-shirt-like garments with interwoven textile electrodes that enable hospital-grade ECG (electrocardiogram) monitoring for patients with heart arrhythmia or palpitations. The garments are comfortable and machine washable.

Photo courtesy of Healthwatch Technologies

The Swiss company Biovotion, award winner in Nokia’s recent Sensing X Challenge, demonstrated a device worn on the upper arm loaded with specialized sensors that monitor physiological parameters. The current version measures five parameters and the next-gen device expands this to thirteen.

Photo courtesy of biovotion

Future versions will also allow measurement of blood glucose levels for diabetes patients using patented dielectric and optical spectroscopy techniques. Non-invasively of course, meaning no piercing of the skin and no blood. Present day self-monitoring of glucose is mostly done using test strips and readers. Pharmaceutical incumbents in this multi-billion dollar “strip” market will certainly raise their eyebrows once such technology reaches the street.

The two examples above demonstrate what novel personal medical electronics can achieve based on available technology.

In general, personal monitoring of the following vital metrics is certain to provide telemedicine  with a fresh impetus going forward:

• heart rate
• body and/or skin temperature
• respiratory rate
• ECG (heart arrhythmia)
• blood pressure (hypertension)
• blood glucose levels (diabetes)
• lung volume/spirometry (asthma, COPD)
• oxygen level in blood (asthma, COPD, sleep apnea)
• sleep patterns (sleep apnea)
• sweat (anxiety and stress)

Health insurers will love this technology because it keeps patients out of hospitals or reduces the time they need to spend in hospital, saving costs where it hurts most.

Privacy and security concerns are among the greatest barriers hampering mHealth adoption. They slow down innovation in this field. Understandably. Who wants their health monitored by a smartphone app if the data could be purchased by an insurance company or other third party covertly. Their interest in optimizing profit or increasing revenue might well rank higher than the patient’s well-being. So long as no clear legislation is in place on both national and international fronts that ascribes such abuse as a criminal offense, this promising area of the medical industry will not be able to fully take advantage of the opportunities offered by consumer electronics and match the fast cycle of innovation in the latter field. mHealth is at an important intersection right now. The technology has the potential to radically and effectively change the treatment of many lifestyle diseases which plague industrial societies.

Sensor Hub, Motion Coprocessor or DSP?

In my last blog I referred to the return of digital signal processing in the form of a discrete, low-power chip that acts as co-processor to the main applications processor of a smartphone or mobile device. Taking this one step further raises some fundamental questions. How complex are these helping hands in terms of their signal processing capabilities?

Determining motion

Let’s take the iPhone as an example. The latest iPhone 6 uses the newer M8 motion coprocessor (an NXP Semiconductor LPC18B1 chip) in combination with Apple’s very own A8 / APL1011 applications processor as outlined in a recent teardown by TechInsights. The word motion provides the first clue regarding the primary purpose of the chip: monitoring movement to determine if the user is sitting, running, walking, cycling or driving. In fact iPhone apps interrogate this user activity status from the CMMotionActivity class offered by the iOS operating system. To determine user activity, the motion co-processor will most likely take acceleration readings in three axes (x, y and z) from the accelerometer sensor. Repetitively calculating the max and min values will enable distinction between sitting and running/cycling and driving, regardless if the user is holding the phone, has it stashed in a trouser pocket or nestled in a car’s device cradle.

However it’s far more difficult to distinguish between running or cycling as the acceleration in all three axes is quite similar for both activities. This is where measuring yaw (rotation) using the gyroscope sensor comes into play. Cycling has a smoother repetitive motion than jogging. By calculating the spectrum of the yaw rate using an FFT (Fast Fourier Transform), cycling will show a single dominant frequency as determined by the cadence of the cyclist. Of course calculations can be further relaxed if likelihoods are taken into consideration. For example, a measurement showing an impromptu change of states from cycling to driving is somewhat implausible. Statistical models as offered by Bayesian probability inference or Markov chains come to the rescue here. And if all goes wrong and a confident activity guess is out of question, iOS luckily provides the state unknown.

The M8 LPC18B1UK chip is based on ARM’s Cortex M3 core. In contrast to the follow-up Cortex M4 core, the M3 does not include a DSP instruction set. So, it ’s plausible that activity tracking calculations are performed at a low frequency. In fact the chip is clocked at only 0.15 GHz. That in turn makes it battery efficient so it can run constantly without ever taking a break. Even in the iPhone’s standby mode it collects, calculates and caches sensor data. The iPhone stores results for a maximum period of seven days in the LPC18B1UK’s on-chip flash of 1 MByte. Sampling rates of 14-bit accelerometer data are thus probably in the 1 to 2 Hz range. In other words, really slow.

From lightweight processing to heavy lifting

As the iPhone 6 example above underlines, motion detection is all about lightweight processing. Similarly Atmel’s sensor hub solution as found in several smartphones from Samsung (see Wikipedia) use Atmel’s SAM D20 which features an ARM Cortex M0+ core on-chip and no DSP functionality. However Atmel’s sensor hub roadmap points to the follow-up SAM G51/53 which is based on the DSP-rich ARM Cortex 4 core. Sensor hubs are evidently transitioning from lightweight DSP processing to heavy DSP lifting. Recent smartphones from HTC, Nokia, Samsung and Sony confirm this trend: they use Qualcomm’s Snapdragon 800 SoC (system-on-chip) family with an on-chip sensor engine based on their powerful 32-bit Hexagon DSP core that also offers floating-point support. Next-generation smartphones, wearables and other mobile electronics will thus not only capture both user and environmental sensor data but also combine these streams in an eclectic signal processing mix to provide never-seen-before smarts for the user.

Sensors and the Rebirth of the DSP

Back in the nineties the digital signal processor (DSP) had its heyday. It was a completely different beast compared with CISCs (complex instruction set computers) like Intel’s Pentium or RISCs (reduced instruction set computer) like ARM’s IP cores. DSPs allowed complex mathematical algorithms to be processed in real-time based on the fundamental mutliplier-accumulator structure of their internal architecture. Mostly these signal processors had a 16-bit fixed-point word length with a very basic feature set. Their distinctive clout was speed combined with low power - a boon for all types of embedded applications requiring real-time response. Yet their restricted word length made programming them an art, something for maths whizz kids who could work with integers just as well as with floating point numbers. And then at some point, stand-alone DSPs simply disappeared off the processor map. What happened?

Layed off by semiconductor advances

With each reduction in size of semiconductor processing nodes, clock speeds moved into the gigahertz range whilst supply voltages and power consumption dropped dramatically. Lower power levels and longer word lengths enabled newer processor types and categories to extend their reach into the domain of rigorous real-time requirements, formerly a unique terrain for digital signal processors. Multiple cores on the same dice were suddenly feasible and the stand-alone DSP simply got gobbled up in the process. What was once a stand-alone math starlet enjoying the limelight became reduced to a common (and essential) block on a larger system-on-chip (SoC).

Smartphones and their sensors

Recently I’ve noticed the term “DSP” appearing more frequently again in the semiconductor world. The trail leads back to sensors; in particular, sensors as they are used in smartphones. First -generation devices featured three or four sensors to ensure fluid interaction with their touch screens: a proximity sensor to turn off the display during a call for saving power and preventing contact with the ear or face; an ambient light sensor for the best reading experience under all types of lighting conditions; an accelerometer to sense the orientation of the phone and switch between portrait and landscape modes accordingly. With each new device generation, further sensors joined the fold. Recent smartphones are often blessed with over ten such environment watchdogs.

Each new smartphone generation features more sensors

Sensors provide information on what the user is currently doing. Combined with location intelligence, smartphones can react intelligently to the user’s activity and current surroundings. Continuous sampling, storage and processing of sensor data is necessary in order to keep track of what is happening to the device, its user and whereabouts. Keeping the phone’s main processor- one of the battery hogs - on all the time, makes no sense. Enter the power efficient coprocessor, often termed sensor hub, or motion processor and sometimes even DSP.

Fusing sensor data to predict location

By adding an additional processor with scanty energy demands operating separately from the main, power-hungry applications processor, the continuous flow of sensor data can be analyzed all the time, even when the phone itself is asleep. Sharp readers will contest why use a processor geared towards blistering speed (read DSP) if sensor data, like readings of the temperature or magnetic field, arrive at a snail’s pace? Yet most calculations are all about sensor fusion, or using multiple sensors inputs to determine something really useful. Take indoor navigation as an example. The usual satellite GPS signal may not be available yet seamless navigation might still be required. Using combined data from the accelerometer, gyroscope, magnetometer and pressure sensor, the DSP implements a mathematically complex Kalman filter to accurately estimate the user’s position from previous bearings (dead reckoning algorithm) and simultaneously compensates for a number of tricky sensor anomalies such as offset, gain, non-linearity and noise. Such an intelligent sensor hub provides rich soil for further smartphone differentiation to take root as algorithms and smartphone apps combine motion, physiological (e.g. heart rate, voice analysis, …) and environmental data in completely new ways. This new trend brings the digital signal processor (DSP) back into the spotlight, reestablishing it prowess from its former glory days as a highly power-efficient mathematical engine.

Apple's Watch and Sensor Magic

Slated for release in early 2015, the Apple Watch will certainly raise eyebrows in many ways, possibly heralding in the consumerization of smartwatches. The company’s general mobile philosophy has been to cram more sensors into products than most of its competitors do. By integrating sensors, users not only carry a desktop computer in pocket format with them but a truly smart mobile device.
One of the more novel sensor solutions on-board the Watch can be seen on the back of its stainless steel and alumium casing: an optical system consisting of a combination of LEDs and photodiodes that gather data from both the visible and infrared spectrum.

Apple Watch’s LEDs and photodiodes for heart rate measurement

Photo courtesy of Apple, Inc.

With these sensors the Watch becomes a fitness device capable of measuring the user’s heart rate through optical sensing. In very basic terms this means shining a light through the skin of a user’s wrist and monitoring the change in blood flow in order to determine his or her pulse. It’s all about addressing today’s trend of the “Quantified Self” by continuously logging one’s daily activity as a means to improve basic fitness or even workout endurance over time. Electronic activity trackers are mostly sold as wearable bands today from the likes of Fitbit, Jawbone and Nike , but smartwatches and bands will converge at some future point. In 2014 around 10 million activity tracker bands will be sold worldwide and this figure is expected to triple in 2015. The market segment is set for exponential growth.

The smartwatch as a meaningful medical device

Lower-cost wrist bands are mostly attractive for those obsessed with tracking their activity and exercise. Yet will smartwatches such as Apple’s Watch also address real patients or the elderly who’s medication regime depends on regular and accurate monitoring of heart rate, blood pressure, blood oxygen levels (oximetry) or even blood sugar (glucose)? Two announcements provide some clues on this potential. Firstly, Apple has silently been hiring medical sensor experts over the past few years. The Apple Insider article identifies that a number of these hires were previously employed with serious medical companies. Secondly, Apple has filed a slew of patents related to medical monitoring over the past years. Patently Apple reports on several health and biometric-related patents in this area. Skeptics however purport that accurately measuring heart rate, as an example, is a big leap from the techniques that fitness trackers employ, maintaining that doctors rely on electrical not optical measurements for accuracy. Wearing a device on one’s wrist for correct pulse tracking requires it to be strapped very tightly so the sensor cannot move around during measurements. In addition, as users who measure blood pressure know, wrist measurements can be off from their true value by quite a bit because blood flows a lot slower by the time it reaches the body’s peripheral zones like the wrist. Many open questions and much room for speculation remain. Mike Nicholls of startup88 provides some “can’ts” why the Watch won’t cut it on the medical front. Are there any cans?

Many sensors make light work

Whilst accuracy imposes certain onerous requirements, it’s probably shortsighted to brush off the Watch’s possibly far-reaching medical potential. Point in case: today’s smartphones do not determine user location single-handedly by satellite (GPS) but in combination with input from other embedded sensors. Using complex calculations, data from their accelerometer, gyroscope, and magnetometer predict the user’s current position based on his previous one if a GPS signal is not available (dead reckoning). Multiple sensors termed as a sensor hub in combination with a power-friendly, always-on dedicated processor running signal processing algorithms can work sensor magic - possibly even medical magic. The Apple Watch is rumoured to have more than 10 sensors and will most likely also feature a motion coprocessor like the M7 (iPhone 5S) or M8 (iPhone 6). Combined with Apple’s talent pool of medical expertise it’s highly likely we can expect some surprises on the road ahead. If not in a 1st generation Watch, then for sure in its later product cycles.

Who Needs a Smartwatch?

Touted as the next big wave of consumer devices to impact our lifestyles, smartwatches will supposedly change many of our daily habits. Or will this be just one more device that finds it way into some drawer of collectibles after a few weeks of use? 

Examining my own behaviour, I have to admit that I always wore a wrist watch until the day I became the proud owner of my first cell phone. On that veritable day my cheap wrist watch became a forever companion to the special-occassion premium model in my bedside drawer. Yet recently I rediscovered the convenience of strapping a regular watch to my wrist to tell the time. A quick glance instead of fumbling for that phone slate somewhere deep in a pocket.

Hands freed up at long last

If you're on the go, there's a certain magic to having both hands free from carrying things like a luggage item or a phone. Smartwatches have the potential to deliver on that promise. In addition they they will be so much more than just an elegant timepiece.  Having a launchpad for calls, guidance, management and diversion strapped to one's wrist is a tempting thought. And a few clicks, swipes or voice commands could initiate all the fun. If regular wrist watches with a brand name cost 100 Euros at the lower end of the scale, then surely 300 Euros is a consumer-friendly price tag for a watch with smarts?

I’d be an easy mark for a smartwatch if

• it offers full functionality without my smartphone, unless I want to make/take calls or access the internet.
• the casing and industrial design in no way resemble an electronic device. As all smartphones resemble rectangular slates, it’s a fitting time to break out of the uniformity mould and revive lifestyle regalia.
• it powers itself through a kinetic mechanism or energy harvesting. As long as I never have to charge it.
• it unfolds a whole new world of “hands-free” functionality for
  • phone calls (missing parts: the Bluetooth earpiece that invisibly clips behind an ear or integrated in an eyeglasses’ arm, and some kind of highly directional microphone that won't require any strange gestures so that the person on the other end understands me)
  • effortless and efficient contactless payment
  • finding my way whilst walking or cycling
  • helping improve fitness or basic monitoring of health (heart rate, blood pressure, glucose level...)

My short list above might one day appear quite meek. Equipped with a multitude of sensors, smartwatches will see unthought of functionality unfold as creative developers build new applications using development kits that the manufacturers provide. The beauty of “smart” in smartwatch means different designs, different functions, different uses for different types of users.

Apple Watch	Samsung Gear S	Moto 360	Asus ZenWatch	LG G Watch R
Photo courtesy of Apple	Photo courtesy of Samsung	Photo courtesy of Motorola	Photo courtesy of Asus	Photo courtesy of LG

From Swatch to Rolex: will smartwatches ever span the breadth from the low-cost to the up-market?

Visitors to the Mobile World Congress earlier this year could witness smartwatches and fitness gadgets galore on display. Apart from the trendy fitness band, I have yet to see any of my personal acquaintances sporting a smartwatch. Will the announcement of Apple’s Watch for next year change consumer behaviour at the flick of a switch as they so often have proven before? 2015 might indeed provide the spark to catapult smartwatches and wearables into mass adoption.

Smartwatch and Wearables Shipments

Smartwatches fall into the so-called category of "Wearables" that many technology market research companies track. Forecasts vary and inflated expectations are sure to traverse a temporary trough before certain mass adoption occurs. Various sources suggest that around 10 million wearables were sold in 2013 with sports and activity trackers topping the list. Looking further into the future, opinions differ on the potential market size. Bold seers predict over USD 100 billion of wearable device revenue for 2018, whilst the more cautious cap their forecast at USD 30 billion. Compared to 2013 smartphone revenues of roughly USD 300 billion (around 1 billion smartphones were sold at an average price of USD 300) smartphones overshadow wearables considerably, but for how long?
On the smartwatch front Generator Research provide a short yet comprehensive history and outlook for smartwatches (free). The market research outfit’s recent study Smart Watches: 2014 forecasts sales of 5.8 million devices worldwide in 2014, rising to 313 million by 2020.

Sample Market Research on Wearables

Wearables Service	CCS Insights	http://bit.ly/1ou2S2b
Wearable Computing: Technologies, Applications and Global Markets	BCC Research	http://bit.ly/1qReqfq
Investing in Wearables for Financial Services	Javelin Research	http://bit.ly/ZnzAMS
Wearable Computing: Fitness and Health in Style	Parks Associates	http://bit.ly/1nEvg71

On wi360 you’ll find many more report summaries that focus on wearables and smartwatches providing insight and opinions into a consumer market segment that is set to boom.

Designed in China - Assembled in China

Fueled by WhatsApp peer pressure, our ten-year old recently bought his first smartphone. Make: Huawei. Price: Euro 70.00 without a plan/contract. Performance: admirable. Anyone used to Apple’s macrocosm will find it hard to believe that a smartphone can retail at that price. Mobile phones in Europe used to be all about Nokia, Ericsson, Motorola and Siemens. Then came Apple and Samsung. Names disappeared. Now it’s China’s turn in changing the handset game.

A common Western misconception

“Made in Hong Kong” was imprinted on many of the toys in my boyhood days (way back in the seventies). Then this label was synonymous with “cheap”, “plastic”, “throw away after light use”. At that time China meant little more to me than the occasional meal at a restaurant, the timeless wisdom of a nation as portrayed in the sayings of Confucius, or the iron-fisted communism and class struggle headed by Chairman Mao. Quite frankly, today China is much more than world’s manufacturing workbench. It’s well on its way in advancing to a major R&D force whose impact is beginning to be felt by high-tech consumers around the world. Are the days of “Designed in California - Assembled in China” numbered?

China: think big, think volume

When a topic touches something as vast and far away as China, it’s tough staying grounded and getting the facts right. Clearly China not only has the brains, capability and drive to impact technology worldwide. More than that it has an immense end-user base at home that allows scaling volume production into realms unthinkable for many of us in the West. Case in point: China Mobile boasts some 750 million subscribers. That’s on par with the total population of Europe! Imagine, one single wireless operator with this sheer number of customers at the controls of mobile voice, messaging, apps, handsets and other desirable services.

Reaching out and moving in

On the infrastructure side Chinese companies like Huawei and ZTE have already made inroads in foreign markets. I remember their sleek offices quietly opening in Dusseldorf on the river Rhine several years ago. Price disruptions in telecoms infrastructure followed and ever since Alcatel-Lucent, Ericsson and NSN (Nokia Solutions & Networks, formerly known as Nokia-Siemens Networks) have been feeling the bite at their established clientele. Yet it’s not all threat. Flip the coin and China’s colossal market offers tremendous trade opportunities for foreign companies.

Telecoms market research on China

In wi360’s research and event directory you will find many studies from various sources that provide a detailed view of China’s mobile and wireless landscape. Here are a few sample results when entering “China” in the Search field for Reports at wi360 .

• China Telecommunications Report from Business Monitor International provides an overview of the Chinese telecoms market. In addition it profiles 19 MVNOs (mobile virtual network operators) in the country.
• China’s top five vendors account for 20% of the world’s smartphone shipments from Canalys ranks smartphone vendor shipments and growth in China’s domestic and foreign markets
• The Mobile Industry Alliance’s (MEA) Certimo benchmark measures user experience ratings for popular Android smartphones sold in China from manufacturers such as HTC, Huawei, Lenovo, LG, Meizu, OPPO, Samsung, Sony, Vivo, Xiaomi and ZTE, and these have been published by Tencent, China’s largest Internet portal. Results can also be found on MEA’s website.
• Consumer Demand Analysis of Smart Wearable Devices in China is a survey from MIC - Market Intelligence & Consulting Institute in which Chinese consumer purchasing behaviour with respect to wearables is profiled
• TD-LTE Market Developments and Forecast, 2014–2016 from Digitimes details mobile networks based on China’s homegrown TD-LTE standard and their outlook in 17 further countries where they have been deployed
• Strategy Analytics’ report titled China Mobile’s One Man Show to End reveals the strategies of China’s three operators regarding LTE FDD (note: not TD LTE) infrastructure in the country
• Global and China EMS and ODM Industry Report, 2013–2014 from ResearchInChina takes stock of manufacturing services for consumer electronics in China, Taiwan and other countries around the world

Understanding China and its wireless markets as well as the companies, services and products that comprise it mobile ecosystem is an important step in spotting and tapping potential opportunities and participating in the country’s unquestionable growth in trade. Western manufacturers may even be at an advantage in being able to produce high-quality kit at much lower production volumes that allow product customisation and variation. “Designed in California - Assembled in California” could potentially be a prized imprint from the perspective of future Chinese consumers.

Spectrum - private or public beachfronts?

Spectrum seems similar to real estate. At least that's the image that is conjured up by the often used analogy "public or private beachfront?".

You could argue the beach (spectrum) belongs to government (regulator) who should plan its best use for its people, either by selling it off (licensed spectrum) to an investor (carrier) with strict clauses for its development (cellular infrastructure coverage) and ensuing use by paying visitors (subscribers), or by keeping it a public space open and free to all (unlicensed spectrum). This seems like a pretty good analogy but it seems to ignore one key contributor that is throwing a spanner in the works: technology advancement, or more accurately, semiconductor improvements. Wireless data is exploding through the usage of new wireless handhelds and devices and there is no end in sight. The Internet-of-Things is looming, further intensifying the situation as seers predict everything with a current running through might potentially be a source of further wireless data. So all sights are set on "spectrum" to offer a cure, and governments (regulators) who ultimately own it. Indeed, we need more spectrum. And lots of it.

Spectrum is big money

Spectrum is where big money meets legislation meets high-tech, yet always bound to the perennial laws of physics. It's a billion-dollar industry that encompasses auctioning, immense investments for operators who build nation-wide networks, influenced by a constant stream of new technologies that improve connectivity for all. Proponents of the one camp (licensed) rightfully argue that the immense investments for carriers building nation-wide networks require long-term perspectives for ensuring a profitable business. The other side (unlicensed) maintain that only open policies guarantee fair and efficient use of the airwaves and lead to universal, affordable and ubiquitous broadband for all. A case of "Cellular" vs. "WiFi" is in the ring for the next round.

"Spectrum Crunch" - a myth?

The crux of the issue is that much of our spectrum, particularly around the "sweet spot" is already in use. At least that what the skeptics purport, creating a shortage or "spectrum crunch" myth. The truth is a little more varied and subtle though.

Click to enlarge

Radio spectrum extends for 3 kHz to 300 GHz and mobile phones currently operate between 700 MHz to 2.6 GHz in this range - the so-called "sweet spot" based on state-of-the-art technology. Note, that this sweet-spot spectrum block represents roughly just under 1 % of available "radio spectrum". Spectrum shortage? Well, yes, in a way, if  you regard what's exploitable using today's available technology. Just as broadcast AM radio in the early decades of the last century relied on valves and tubes for frequencies up to 15 kHz, today's semiconductor technology defines wireless communications around the 1 GHz mark. But what about tomorrow? 

First approach: making the best of "redundant" spectrum

To date specific blocks in the full radio spectrum range have been allocated for specific purposes or services by governments, and most of these are historical in context. For example blocks for maritime navigation, aeronautical navigation, public safety, broadcast TV etc. A true patchwork as can be seen in Sebastian Anthony's "wireless crunch" blog for ExtremeTech. Of course spectrum is a unique and therefore valuable resource, but it does differ from oil, gas, minerals etc. which face continuous depletion until none are left. Spectrum can be revitalized by closing older, inefficient services, as has or is being done for analog TV, or by making use of "white space" consisting either of unused spectrum blocks or guard bands between used blocks/frequencies that were required in prior times for broadcast and communications technology to work.

Technology advancements increase spectrum usage

As the needle of technology heads towards the future, better usage in existing spectrum blocks and new usage in regions higher on the spectrum map become available accordingly. Ever decreasing semiconductor process nodes ensure the implementation of mathematical algorithms providing better modulation techniques and other advancements that ultimately increase bandwidth and bit rate per Hertz of frequency. Of course at the heart of cellular and wireless communications is the trade-off in providing the best capacity (more bandwidth/higher bit rates using higher frequencies) for the largest possible coverage area (lower frequencies are better here). Broadly speaking, lower frequencies travel further than higher ones but cannot carry as much information. The current sweet spot for wireless communications is determined by these facts and primarily governed by what's technically possible based on state-of-the-art semiconductors. Advances in semiconductor technology will allow the sweet spot to travel further up the spectrum over time and provide better bandwidth. The diagram below shows how these advancements will ultimately lead to the still amorphous 5G technology as we get closer to the year 2020 where wireless Gigabit speeds will become reality.

Click to enlarge

Does your devices' antenna size still matter?

Fitting a large antenna or satellite dish on your roof works for great TV reception, but what about handheld/portable wireless communication devices? One of the limiting factors of wireless devices has always been the required size of the antenna for transmission and reception. Antennas "resonate" at one quarter of a frequency's wavelength. Taking this factor into account for the typical current "sweet spot" frequency at 1 GHz leads to a minimum necessary antenna size of 7.5 cm which resembles an acceptable cell phone size. At 300 MHz this increases to 25 cm whereas at 3 GHz we get down to 2.5 cm. In other words, higher frequencies spell out smaller device form factors, or more room for integrating antenna arrays, read MIMO et al. As these new antenna technologies come into play, data rates can be increased through better wireless performance in several respects, irrespective of the maximum bit rate achievable by the modem dictated by modulation techniques/Shannon's theorem.

Some worthwhile spectrum vs. technology resources

Spectrum, it's allocation, management and better exploitation through technology is a complex field in itself. Both free and subscription-based resources provide great insight into the issues at hand. Regarding today's 4G technology, we've reached the max in terms of squeezing as many bits as possible per Hertz of spectrum, as eloquently reported by Kevin Fitchard at Gigaom on wireless networks as workhorses of the web. A further great reference is Frank Rayal's blog looking at the capacity-coverage issue for licensed and non-licensed band. It investigates and compares differences in this respect for LTE and WiFi, both using a 20 MHz band. Certainly both camps have convincing points to advocate as we move further down the timeline. Telecoms and spectrum expert Gunjan Idrayan writes a regular insightful blog on spectrum and wireless with a particular focus on the situation in the United States and India. You'll also find some timeless articles about licensed and unlicensed spectrum as well as mobile broadband written by Peter Rysavy. Furthermore here's a short list of paid research that is well worth investigating if spectrum belongs to the core of your professional work.

The Global Spectrum Database PolicyTracker	http://bit.ly/THmNBb
Spectrum Auction Tracker Analysys Mason	http://bit.ly/1t5EQkV
2G, 3G, & 4G Mobile Network Subscriptions, Spectrum Licensing, Ownership, Infrastructure Contracts & Handset Shipments Database Signals and Systems Telecom	http://bit.ly/1lEZ63o

Spectrum for Mobile Broadband IDATE	http://bit.ly/1lEZGhx
Radio Spectrum Intelligence Tolaga Research	http://bit.ly/1mR4sc9

There are many more market research reports on the topic of spectrum available, and you can also stay on top of the latest worldwide events by signing up at wi360 (free). You will receive email alerts on new research and events regarding the specific topic of spectrum.

Spectrum's future

Governments that regulate spectrum and the technology sector that provides the devices for wireless access are both doing their best by squeezing the most out of a limited resource. Yet each of them works with a completely different heartbeat and thus the "divide" is increasing at an alarming level to the detriment of the consumer and subscriber. Wi-Fi over the past decade is a case in point how unlicensed spectrum has been addressed remarkably well at breakneck speed outside of government intervention. At the same time, network investments in the licensed spectrum must also remain a lucrative business for carriers. With the subscriber in mind, the golden age of raking in exorbitant cash amounts by governments through spectrum auctioning requires a future rethink.

Our spectrum future will be mapped out how well concepts from all parties will be mutually respected and implemented.

Supercharging Cellular Networks

Smartphones are great - next to that essential phone call, they give us email and Internet access on the go, updates on friends through social media, help in finding the way to a new restaurant, and a plethora of other useful features. On the other side, they give operators the challenge and headache of how to solve congestion on their cellular networks. Apple's first iPhone, its touchscreen, its app concept, marked an iconic game change in the industry, not only for the user, but even more so for cellular infrastructure. Its introduction opened the sluice gates for mobile data demand, and ever since the need for more bandwidth on networks continues to surge.

 

Small cells: from micro to femto

Not only do small cells offer operators a way out of the data crunch dilemma, but they also improve call reliability and quality indoors where mobile connections often fall victim to weak reception.
Femtocells surfaced first, as far as I can recall,  and they were toted as technology to storm consumer's homes for solving weak indoor signals. Metrocells, considered femtocells with an increased range, followed on. Then microcells and picocells. Nanocells seemed missing on most product roadmaps. In strict math terms, micro is one millionth, nano one billionth, pico is one trillionth, and femto one thousand trillionth. In other words, each metric prefix is one thousandth smaller. This appears to be linked in no way to small cell technology rationale, or their coverage range, and is probably a marketing ploy for naming small, smaller, smaller still... Good thing that these monikers with their differing and overlapping definitions were all placed in the superset "small cells" at some point.

Small Cell Classification	Typical Range
Microcell	2 km
Picocell	200 meters
Femtocell	Several tens of meters
Reference: a base station macrocell has a typical range of ca. 35 km

 

Many shapes, sizes, scenarios

Essentially small cells provide an opportunity in solving mobile network overloads by adding further access points (read base stations) within the cellular operator's macro network at a higher cell resolution or smaller range. That's a very simplified view.

Small Cells: different formats, different deployments, different approaches
Residential Sagemcom AP2820V plugs into an AC socket: 8 calls in parallel, 7.2 Mbps, 30 meter range Photo courtesy of Vodafone	Enterprise Ericsson’s “Dot” solution is a radio-only access point connected to an "enterprise base station" and powered by LAN Photo courtesy of Ericsson	Outdoor Rural Ubiquisys' Tecom FC1080 outdoor solution with coverage up to 3km – 16 voice calls, 14.4Mbps HSPA Photo courtesy of Ubiquisys

 
This plain picture becomes more complex when other forces are factored in. Are we dealing with indoor or outdoor coverage? What about using Wi-Fi and public hotspots in the unlicensed spectrum as a cellular network offload? How do you connect these small cells to the operator's existing macro network (backhaul) and best manage and dynamically allocate bandwidth? How to find and deploy new sites for small cells and make sure they provide a profitable perspective?

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Each scenario comes with its own set of specific challenges. To further the cause of expediting roll out of small cell technologies, the Small Cell Forum was founded in July 2007 by the companies Airvana, ip.access, NETGEAR, picoChip, RadioFrame, Tatara and Ubiquisys. The group has done some great work to address these challenges by providing concrete return-on-investment and best practices technology guides for residential, enterprise and public scenarios. Notwithstanding, even many years down the road it is evident that the manifold challenges facing small cell deployments are hindering their adoption. Yet time is playing into the hands of this technology as an efficient means of solving the data bottleneck.

 

Highly-integrated small-cell SoCs bring equipment cost down

Semiconductor vendors such as Cavium, Freescale, Mindspeed and Qualcomm are addressing the nascent market with offerings that combine 3G or 4G (LTE) technology with latest WiFi standards (802.11ac and 802.11n) on a single piece of silicon or system-on-a-chip (SoC). Combined with the a transceiver and power amplifier for the RF section and other ICs for the type of backhaul desired, they deliver a complete base station in a compact, access-point format. A central theme of all such designs is their focus on energy efficiency. As such they employ a number of smart schemes to mimimize energy consumption so that power requirements don't impede the small cell uptake in homes or their placement on so-called street furniture (lamp poles, building walls etc.).

Small cell market research

The market for such equipment will indeed become huge. The research company Infonetics expects a $3.6 billion worldwide spend on small cells during the period 2013 - 2017.
Monica Paolini, founder of Senza Fili Consulting, contends that small cells will need Wi-Fi to succeed, as its uses license-exempt spectrum, a technology that is still not a close chum to many cellular operators. Small cells and their operators will eventually accept the wisdom of utilizing ubiquitous Wi-Fi and find ways to solve the complex interoperation between macrocell, small cell, and Wi-Fi elements to deliver adequate bandwidth and seamless handover whereever one may be. Such solutions are coined as wireless HetNets (heterogenous networks).
Other research outfits such as iGR are acutely aware of the cost of deploying sites that is hindering small cell roll out. Their scenarios breakout the cost in detail based on small cell type, backhaul (fiber or microwave), backhaul speed, labor and installation, power and ancillary equipment expenses.
Analysts at Tolaga Research point out that the industry requires an average $5,000 target site cost for small cells to succeed and the backhaul contribution should constitute no more than 20-30 % of this figure.

 

Reports galore

There is a lot of market research available that proves the smattering of small cell alternatives available and implementation scenarios.

Over 50 research reports covering Small Cells at http://www.wi360.org/

Small cell events

Equally many events are going to be hosted in 2014 on this subject (see http://www.wi360.org/ too) that keep industry participants in touch with the latest developments in the small cell market.

Ultimately small cells will allow smartphone, tablet and portable computing device owners to stay reliably connected and consume bandwidth no matter where they are or what they do.