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Wireless technology was once synonymous with cellular communications and the portable telephone. But just as cellular networks and cell phones have evolved over the years, so too have the myriad applications for wireless technologies, with wireless connections being made from the shortest distances to the highest frequencies. Wireless equipment suppliers are now faced with requirements that can essentially include frequencies from DC through the millimeter-wave range, with communications distances ranging from less than an inch to back and forth between satellites. Over the next decade, it appears that wireless technology will only continue to expand into a variety of different markets, including commercial, industrial, military, and even medical applications.

Cellular communications systems are in the thick of ongoing buildups based on fourth-generation (4G) Long-Term-Evolution (LTE) equipment and technology. Nevertheless, such companies as Intel Corp. are already promoting the expected capabilities of fifth-generation (5G) cellular networks, even if those networks are not expected until 2020 or later. As the use and ownership of mobile/wireless devices such as smartphones, iPads, and laptop computer continues to increase, the demands for wireless network bandwidth grow, as the available bandwidth is quickly consumed by voice traffic, wireless data, and wireless video communications.

Service providers working with 4G LTE capabilities are exploring the benefits of smaller cell sites and what are being known as heterogeneous networks (HetNets). These are combinations of Wi-Fi stations, cell towers, and smaller cell sites—even, in some cases, wireless base stations located within homes. (See “Building Base Stations For Use In Homes.”)

Intel’s interest in 5G wireless networks is quite logical, given the number of opportunities for the company’s microprocessor chips represented by 5G products. Intel has claimed to have invested at least $3 million so far in support of wireless research towards 5G technologies at more than 10 universities, including Cornell, Princeton, Stanford, the University of Illinois at Urbana-Champaign, and the University of Texas at Austin. Intel is also working in partnership with Verizon on wireless research for 5G, under the auspices of Intel Labs and the recently formed Intel Strategic Research Alliance (ISRA).

Another company with strong belief in the potential for 5G cellular communications, Samsung, has already prototyped portable wireless devices working at 28 GHz. The firm has demonstrated error-free data rates to 256 Mb/s and data rates with minimal error to as high as 512 Mb/s (Fig. 1). These data rates are considerably higher than the theoretical maximum of 75 Mb/s possible with 4G LTE technology, and Samsung claims that its wireless technology can support data rates in excess of 1 Gb/s over distances to 2 km. The well-known tradeoff for such high-frequency signals is high atmospheric attenuation and limited transmission range, along with difficulties in maintaining connections with moving receivers (see “Take The Train To The Internet”), although these prototype tests have been demonstrated over distances as great as 200 m without line of sight and with moving transmitters and receivers.

1. Prototype devices working at 28 GHz are designed to increase the data rates of next-generation wireless cellular systems. (Photo courtesy of Samsung.)

Samsung’s technology, which is sometimes referred to as “millimeter-wave cellular” communications, involves sophisticated beam-forming techniques: Some 64 antennas are used in both the transmitter and receiver, with rapid switching among the antennas. The antennas are switched in a matter of milliseconds as a handset moves, so as to acquire the best signal for the environmental conditions (such as reflections from walls). Of course, one of the challenges inherent to this unique technology approach is finding some means of fitting 64 antennas into a mobile wireless device.

An emerging, rapidly growing segment of wireless technology is in the area of near-field-communications (NFC) applications. This is essentially the use of wireless technology to exchange different types of information—such as telephone numbers, personal files, or payment information—across a short distance, as between mobile telephones or other wireless devices. The technology is centered on the 13.56-MHz frequency of radio-frequency-identification (RFID) devices and data rates to about 424 kb/s at distances to a few inches.  The technology is supported by the NFC Forum, a non-profit industry association started in 2004 by Nokia, NXP, and Sony; members include Verizon Wireless and Discover Financial Services LLC.

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