Wireless everything—that’s the theme and direction the electronics industry is taking. Practically all new products have some form of wireless component or option. For example, Apple’s Hue is a set of three Philips LED light bulbs that can be controlled from an iPhone or iPad.
Hue uses Wi-Fi to talk to a wireless bridge supplied with the bulb set that in turn connects via the home router. The bridge also connects via a ZigBee wireless link to the light bulb to turn it on and off and control its brightness and color.
The smart phone is at the center of all this wireless activity. More than 50% of U.S. cell-phone subscribers have a smart phone, and that percentage is growing in the U.S. and in the rest of the world too. The smart phone has clearly replaced the PC (desktop or laptop) as the top consumer electronics product.
Perhaps we should begin calling the smart phone what it really is: a compact portable PC with communications capability. Those hundreds of thousands of apps that are currently available run on a computer, not a phone. While the smart phone dominates the wireless space, though, other wireless technologies continue to grow and find new applications.
Smart-Phone Growth And LTE Rollout
Cell-phone growth will continue throughout 2013. A recent report from Ericsson indicates total global mobile penetration of 91% as of the third quarter of 2012. Total mobile subscriptions are now 6.4 billion, and that’s expected to grow to 6.6 billion by 2018. China and the U.S. lead in subscriptions.
Furthermore, 40% of the phones sold in 2012 were smart phones. LTE subscriptions grew to 55 million in 2012 with a total of 455 million people with LTE coverage by mid-2012. Subscriptions for LTE are expected to reach 1.6 billon by 2018.
As LTE is rolling out, though, 3G technologies are still growing. HSPA and other 3G networks provide near LTE performance at a lower cost that is suitable for many users in many locations. 3G will be around for many years more, but the older 2G technologies will gradually fade away.
Research firm Gartner says that Samsung is the leading handset manufacturer, including smart phones, with Nokia a close second in the world market. Apple is a distant third followed by ZTE, LG, and others. Sales figures by handset operating system (OS) show Android clearly in the lead followed by Apple iOS, RIM’s BlackBerry OS, and others. You also may expect to see some new players in smart phones. Both Amazon and Microsoft are rumored to be working on their own phones for later in 2013.
Screen sizes continue to grow to 4 inches and beyond to a maximum of 5.5 inches for the Samsung Note II. It is doubtful sizes for smart phones will go beyond that size, though. If you want bigger, try a tablet for video and other applications requiring a larger screen.
Most newer smart phones include LTE, the 4G technology now being added to and expanded in most carriers’ networks. Verizon is still in the lead in the U.S. with the most LTE sites, but AT&T is not far behind. Other carriers like Sprint will begin to offer LTE, as will T-Mobile and its recent acquisition, MetroPCS. 2013 will see major expansions of all these LTE networks as well as an increasing number of new LTE handsets. More subscribers will opt for LTE despite the growing cost of data plans.
Near-field communications (NFC), the short-range technology designated for mobile commerce, will continue to make inroads as more smart phones incorporate it and as more retailers add terminals and back office systems to accommodate purchases with cell phones instead of credit cards. However, NFC won’t be a universal feature like Wi-Fi since Apple has not and probably will not adopt NFC for its iPhones.
While the LTE expansion won’t be complete by the end of 2013, there is word of some early deployment of LTE-Advanced (LTE-A), the next version of LTE. LTE is really just a 3.9G technology. LTE-A is the real 4G according to the Third Generation Partnership Project (3GPP), which develops and sets cell-phone standards.
LTE-A’s carrier aggregation permits cell sites to assemble up to five 20-MHz LTE channels into a single channel. The channels may be contiguous or non-contiguous as applicable to the carrier’s spectrum holdings. Added to that is an 8x8 multiple-input multiple-output (MIMO) option. And, LTE-A offers up to 1-Gbit/s downloads under optimum conditions.
LTE-A is not deployed yet, but formal service is expected to begin in limited areas in late 2014 (see “Design Trends Address Challenges In Cellular Products”). Still, LTE and LTE-A both present multiple design challenges, like Voice over LTE (VoLTE). LTE is an Internet protocol (IP) data network only. The older 2G and 3G GSM and CDMA voice systems carry voice. VoLTE will eventually lead to the phase-out of these older technologies.
Smart-phone sales by units and revenue have exceeded those of PCs, according to Barron’s. Also, more users access the Internet via their smart phones than their PCs. Smart phones and tablets are causing PC sales to decline, and that decline will continue. PC sales will never go away, but most manufacturers are scrambling to find alternative business models and products.
Small Cells And Wi-Fi Offload Form The HetNet
What may become the real 5G standard is the forthcoming adoption of small cells—tiny basestations called picocells, microcells, and femtocells—that can be located anywhere that traffic requires them. Small cells will fill in the gaps between the current standard macrocell basestations to create what is being called the heterogenous network, or hetnet. Wi-Fi offload is part of that solution.
There could be as many as three small cells per macro. Such an arrangement will permit broader and more reliable coverage as well as much higher data speeds to accommodate the growing demand for video, gaming, and other massive data applications. Hetnets don’t exist yet, but the number of picocells and home femtocells already has exceeded the total number of existing macrocells.
Look for an even finer grain of small cells moving forward. Small-cell study, development, and trials will continue in 2013 with the earliest deployments in 2014. However, all of these small cells could lead to massive interference. Home femto cells haven’t resolved the issue yet, and things could get ugly with a massive small-cell deployment.
Wi-Fi and offloading will be used to fill the data capacity gap until more carriers get LTE or an expanded LTE system. If a subscriber accesses the Internet for some video via the 3G or 4G network but an accessible Wi-Fi hotspot is nearby, the phone will opt for the Wi-Fi connection to avoid loading the cellular system. If no hotspot is nearby, the network will handle the access. IEEE standards 802.11u and 802.21, which have yet to be adopted, address the problem of handing over a connection between the cellular network and the Wi-Fi network.
Offload is not widely implemented yet. The carriers would rather avoid the Wi-Fi unless it is their own local-area network (LAN) to get the income. But the lack of capacity to handle every high-speed request at all times makes other solutions necessary. Until full LTE capability is available, we may see some offload as a stopgap measure.
The use of small cells also leads to the backhaul problem. Home femtocells use the subscriber’s home DSL or cable Internet connection for backhaul back to the carrier. But other small cells need a connection to the system as well. Fiber is preferred because it can easily handle the speeds. However, running fiber in cities and dense suburban areas is often just too expensive and impractical.
As a result, microwave backhaul is emerging as the solution of choice. Small, inexpensive 60-GHz (unlicensed) and 80-GHz (licensed) backhaul radios already are being deployed. These radios use Ethernet and can easily achieve the data rates needed to handle LTE small cells over short distances. Market research company Mobile Experts predicts that carriers will invest as much as $1 billion by 2017 in microwave backhaul.
Ceragon’s FibeAir IP-20C backhaul unit supports the hetnet movement (Fig. 1). It uses multicore processing and 4x4 MIMO with 2048QAM to achieve a 1-Gbit/s over-the-air data rate. It is available for the most common microwave backhaul bands of 15, 18, and 23 GHz.
Microwave backhaul is replacing some fiber in longer-haul networks as well. Even fiber isn’t fast enough for some applications. For example, financial trading between stock exchanges depends on ultrafast transactions. Milliseconds matter. While fiber is fast, the stock exchanges and the traders are finding that microwave backhaul is many milliseconds faster. Many new fast microwave links have been built to replace older fiber.
Spectrum Shortages Linger
The demand for more speed to handle video, Internet access, and other high-data-rate applications has led carriers to adopt the faster LTE systems. Yet LTE needs more bandwidth than older 3G technologies, forcing network operators to find and buy spectrum.
Mergers and acquisitions in the wireless field are often based on one carrier acquiring not only the business but also the valuable spectrum holdings of the acquired company. Yet there is only so much relevant spectrum, and most of it has already been licensed not just to cellular operators but also to satellite and other wireless services.
The Federal Communications Commission (FCC) will have to find and reallocate spectrum to meet these cellular needs. The FCC has promised more spectrum for cellular and broadband wireless, but little has come of that promise. Hopefully the FCC will find useable spectrum and provide an auction in the near future to keep the wireless industry on track for growth.
White spaces can assist in the growth of fixed broadband wireless for Internet access. These unused 6-MHz television channels vary in different localities, so frequency-agile radios are needed to take advantage of them. The total spectrum extends from 54 MHz to 698 MHz, but the channels above 470 MHz are the most useful.
The FCC has declared white space to be license-free if approved equipment meets specific technical restrictions. Several companies are making white space radios to provide wireless services in rural areas and small towns that lack cable or other broadband capabilities.
While more spectrum is the answer to the problem, what happens if the current “good” spectrum from 700 MHz to 2700 MHz is fully used? One solution is to find ways to use the higher frequencies where more space is available. Wi-Fi uses the 5-GHz range, but there is room for additional services.
Transmission range is inherently limited at the higher frequencies thanks to physics, but that may be a blessing as this disadvantage could be the solution to the interference problem afflicting small cells. As cells become smaller and more numerous, it may be possible to use even higher frequencies like the millimeter-wave bands above 30 GHz.
Already, Wi-Fi 802.11ad radios and backhaul for cell sites are using the 60-GHz unlicensed band. Plenty of room is available if the short-range limitation can be accommodated. Shorter range means more radios to provide coverage. In any case, that’s the direction right now.
Furthermore, time division duplexing (TDD) could be used instead of frequency division duplexing (FDD). As used in the U.S. and most other countries, LTE uses FDD, which requires matched and paired spectrum segments: one for uplink and the other for downlink. However, the LTE standard offers a TDD option that time multiplexes up and down links in a single band.
China and other countries already use the TDD option, and more plan to use it. U.S. companies like Sprint and Clearwire plan on using it as well. TDD requires precise timing methods, but they’re well within the reach of most companies. TD-LTE effectively doubles the amount of useful spectrum. This may be a future option for other carriers as their spectrum runs out or as available spectrum becomes more fragmented.
Short-Range Wireless Uses Keep Expanding
Short-range wireless includes Wi-Fi, Bluetooth, ZigBee, and other standards as well as the many proprietary industrial, scientific, and medical (ISM) band technologies. The chips are smaller and cheaper than ever, and the standards are rolling out new applications annually.
Wi-Fi continues its seemingly perpetual growth with the new 802.11ac standard, which uses the 5-GHz unlicensed band now used for 11a and 11n. Along with MIMO, it can produce data rates to 1 Gbit/s over the traditional maximum range of 100 meters associated with Wi-Fi.
Chips are now available, and 11ac already is beginning to appear in some products. Some 11ac access points and routers are available now, but there are few 11ac clients. Eventually, more laptops and ultrabooks will incorporate this technology, but it may be a while before cell phones use it.
Marvell’s 4x4 MIMO 88W8864 11ac chip includes beamforming (Fig. 2). Designed for all manner of access points, hotspots, routers, gateways, and bridges, it can achieve a peak data rate of 1.3 Gbits/s under the best of conditions. The 4x4 MIMO really improves the range and reliability of the connection, and the high data rate makes it suitable for TV connectivity in HDTV sets, DVD players, set-top boxes, and over the top (OTT) Internet TV devices. The device is backwards compatible with 11a/b/g/n devices and features a host CPU offload feature as well.
The future for Wi-Fi is the full deployment of 11ac, but what lies beyond it is difficult to see. Gigabit speeds fulfill most needs, so it’s not clear that more speed is needed for now. Plus, the 1-Gbit/s Ethernet port accompanies most 802.11 routers and access points. In the meantime, 802.11ad is emerging.
Chips for the 802.11ad standard are now available. It uses the 60-GHz band to provide even faster data rates of 1 Gbit/s to 7 Gbits/s over shorter distances in the 10-meter range. Known as WiGig in its commercial form, it targets HDTV sets, video monitors, and laptop docking stations. A combination of 11n and 11ad is available in a modular form for laptops from Qualcomm Atheros and Wilocity. WirelessHD, another 60-GHz standard, addresses various TV and video applications as well.
Wi-Fi is also a good candidate for some machine-to-machine (M2M) applications, including automobiles and cellular offload. This flexible standard shows no signs of fading in the foreseeable future. In fact, because of the ubiquity of smart phones and tablets with Wi-Fi, companies are expanding their deployment of Wi-Fi in the enterprise and in public places. Many new uses are being discovered.
While Wi-Fi may be a mature technology, it is still growing. Research firm International Data Corporation expects the Wi-Fi networking equipment market to total $4.29 billion in 2013 and increase between 10% and 15% per year over the next few years.
Bluetooth continues its reign as the most widely adopted short-range technology, and its increased incorporation continues. With Bluetooth in virtually every cell phone, wireless headset, and tablet, no other wireless technology is so widely embedded. Now with Bluetooth SIG 4.0, the potential is expanding. Most of this potential is the result of a revised version called Bluetooth Low Energy, or BLE (see “What’s The Difference Between Bluetooth Low Energy And ANT?”).
This very low-power version has a slower data speed for sensor applications. Its most likely uses are in the medical market, such as wireless blood pressure monitoring. Sports and fitness applications are also target applications. For example, a chest strap sensor could send data to a Bluetooth watch display to monitor heart rate. BLE could be big since it can easily be incorporated into existing Bluetooth chips in smart phones. Both Apple iOS and Android support BLE connections now. Look for other new uses thanks to this capability (Fig. 3).
ZigBee also continues its slow but steady growth. ZigBee IEEE 802.15.4 radios operate in the 2.4-GHz band with a data rate of 250 kbits/s. With the ZigBee protocol and applications stacks, they have found several key niches including smart electric metering, Smart Grid links, home networking, lighting control, thermostat control, alarm and security systems, and even some special industrial applications involving ZigBee mesh networking applications.
One of the biggest adoptions is RF4CE, or radio frequency for consumer electronics. This standard is designed for the latest remote controls for TV sets, DVD players, audio systems, and other consumer gear. Slowly but surely, consumer equipment companies are abandoning infrared (IR) remotes in favor of the longer range, less directional radio approach. Most new CE equipment will have an RF4CE remote or one that also incorporates IR for backup and compatibility with older equipment (Fig. 4).
Even the sub-1-GHz radio sector is seeing growth in the huge variety of applications, such as wireless shelf labels in grocery stores and other retail establishments. Shelf labels display pricing and other information. The wireless connectivity allows store management to change prices remotely, saving time and labor. Proprietary protocols on 900-MHz unlicensed radios provide maximum range at the lowest of power levels. This is already happening in Europe and will soon emerge in many U.S. stores.
M2M Leads To IoT
Machine to machine (M2M) communications continues to gain ground. M2M technologies remotely monitor and control machines and computers, mostly via cellular connections. Most cellular carriers now offer M2M connection subscriptions for any kind of device or service.
M2M relies on embedded cell-phone modules in vehicles, vending machines, e-book readers, video surveillance cameras, and hundreds of other devices. Most use low-speed 2G digital services, but 3G modules can be deployed where higher speeds are needed. LTE modules are now available from multiple vendors for high-end applications like video.
IMS Research predicts M2M connections to grow from 107 million in 2011 to as many as 326 million by 2016. M2M is the heart of the so-called Internet of Things (IoT) movement, which is expected to see the massive connection of all sorts of devices to the Internet.
Massive Interference Disruptions
With billions of devices transmitting simultaneously in the most popular part of the spectrum (400 MHz to 2700 MHz), look for growing interference problems. Such problems already exist in the almost overused 2.4-GHz ISM band where Bluetooth, Wi-Fi, ZigBee, cordless phones, microwave ovens, and other devices compete. While most new designs provide avoidance or coexistence features to mitigate electromagnetic interference (EMI), it’s only going to get worse as the number of wireless devices continues to increase.
New cognitive radios offer listen-before-transmit and frequency-agile features that further limit most potential interference, though most radios don’t use them. If the EMI problem begins to seriously limit wireless connectivity, look for massive changes in rules and regulations as well as a transition to cognitive radio capabilities.