Most current cell phone carriers offer fourth-generation (4G or 4G LTE) wireless cellular service, which represents the latest iteration in the “exponential evolution” that began with analog first-generation (1G) service in the early 1980s.5 Each subsequent decade has ushered in a new generation of mobile networks, with 2G going digital in the early 1990s, 3G emerging in the early 2000s and implementation of 4G/4G LTE unfolding in the early part of the current decade.
With the advent of the dramatically faster 4G service—the first generation designed primarily for data rather than voice—mobile phone users have been able to stream video and music to their heart’s content.6 Yet, with perpetually data-hungry consumers flocking to newer applications such as virtual reality and videoconferencing, it appears that even 4G is being stretched to its limits.
As the telecommunications industry anticipates “billions of users, billions of devices and billions of connections,”7 it is avidly preparing for the next generation of cellular service, called 5G, which is likely to be ready for rollout well before 2020.8
Far more than a simple technological upgrade, 5G represents a significant and risky turning point with major implications for health, privacy, property values and local control.9 To fully understand what 5G portends, it is helpful to grasp a few basics about the electromagnetic spectrum. Electromagnetic frequencies (EMFs) are expressed in terms of units called hertz (cycles per second), abbreviated as Hz, where the higher the frequency, the smaller the wavelength. The spectrum begins with direct current and extremely low-frequency (larger wavelength) radio waves, and continues with microwave radiation, infrared and ultraviolet light, X-rays and gamma rays. Household appliances are at the extremely low-frequency end of the spectrum, generating EMFs in the range of three to three hundred Hz. Microwave radiation—emitted by all current wireless devices—ranges from three hundred megahertz (MHz) to three hundred gigahertz (GHz). (A MHz equals one million Hz and a GHz equals one billion Hz.)
Unlike prior generations of cellular service, 5G will transmit using not just low-band frequencies but also a form of extremely high frequency microwave radiation called millimeter waves (approximately thirty to three hundred GHz). Millimeter waves offer a “glut” of previously untapped spectrum that the telecom industry is eager to exploit, for at least two reasons.10 First, the “good” spectrum is “just about used up,” according to the communications technology editor at Electronic Design, resulting in “spectrum shortages and conflicts.”11 The tech editor observes that “spectrum is like prime real estate”; millimeter waves can “take the pressure off the lower frequencies” and “provide that precious coveted spectrum needed for expansion.”11 A Samsung-funded wireless expert rhapsodizes, “The beauty of millimeter waves is there’s so much spectrum.”10 Second, millimeter wave technology promises “blazingly” and “insanely” fast data capacity.12,13 Even in advance of its widespread rollout, techies are celebrating 5G’s potential to usher in light speed connectivity14 that is “orders of magnitude” beyond 4G.15
WHETHER WE WANT IT OR NOT
5G’s cheerleaders are particularly delighted with one unique feature of millimeter wave technology, which is that the antennas needed to transmit and receive signals can be very small. At the same time, millimeter waves have one key limitation, dictated by the laws of physics: higher frequencies have much shorter transmission ranges.11