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A cell phone (also called variously mobile phone, wireless phone, cellular telephone, cellphone, cell and hand phone) is

a device that can make and receive telephone calls over a cellular radio network while moving around a wide geographic area.[1]

Historical background[]

The cellular phone was invented by Martin Cooper at Motorola in 1973 and became commercially available in the United States a decade later. First-generation cell phones were primarily used for voice traffic. The transition from analog to second-generation (2G) digital transmission technology, primarily during the 1990s, brought about better sound quality, increased spectral efficiency, and enhanced features like mobile voice mail.[2]

From 1994 to 2000, the FCC auctioned a large number of licenses to use the Personal Communications Service (PCS) spectrum, more than tripling the stock of spectrum available for commercial mobile devices and vastly increasing the capacity to carry digital signals — including voice — over commercial cellular networks.[3] The mobile industry responded with a new wave of innovation and investment, which brought about dramatic change. From 1994 to 2000:[4]

  • The per-minute price of cellphone service dropped by 50%.
  • The number of mobile subscribers more than tripled.
  • Cumulative investment in the industry more than tripled from $19 billion to over $70 billion.
  • The number of wireless providers increased significantly in most markets.

Then came the development and expansion of "mobile broadband." Colloquially, "mobile broadband" refers to “high-speed, wireless Internet.” More precisely, the term "mobile broadband" refers to advanced network technologies, usually at speeds and latencies (amount of delay in sending and receiving data packets) that allow for Internet access and the use of mobile applications ("apps"). The growth of the mobile broadband industry has been driven by a number of factors, including the development of smartphones and other mobile computing devices, the availability of additional suitable spectrum, and the deployment of mobile wireless broadband networks.[5]

In the years since the FCC auctioned PCS licenses, the FCC increased the total spectrum available for mobile services by threefold again — largely through the auction of spectrum in the 700 MHz and 1.7/2.1 GHz bands and the rebanding of spectrum at 2.5 GHz — and this spectrum is coming online for mobile broadband deployment today.7 Most of the major mobile wireless service providers are currently rolling out or planning to deploy new technologies which, by supporting even higher data throughput rates and lower latencies, will facilitate a broader range of mobile applications, such as the viewing of large volumes of video.8 Industry analysts project substantial continued growth of mobile wireless, with data traffic forecasted to increase 35 times 2009 levels by 2014.9

In June 2010, approximately 71.2 million mobile wireless Internet access service subscriptions were reported to the Commission on its Form 477, an 85% increase from the 38.4 million reported in June 2009.10


In addition to the standard voice function of a telephone, current cell phones can support many additional services, and accessories, such as SMS for text messaging, e-mail, packet switching for access to the Internet, and MMS for sending and receiving photos and video. Most current cell phones connect to a cellular network of base stations (cell sites), which is in turn interconnected to the public switched telephone network (PSTN) (the exception is satellite phones).

There were more than 850 different certified mobile products in the United States in 2009.[6] In that same year, approximately 172 million mobile phones were sold in the United States. Of these, 27% were Internet-capable smartphones.


A cell phone contains one or more computer chipsets — the core electronics that allow it to transmit and receive information, either telephone calls or data, to and from the wireless network.

How cell phones work[]

When a cell phone is powered up, it acts as a scanning radio, searching through a list of control channels for the strongest signal. The cell phone re-scans every seven seconds or when the signal strength weakens, regardless of whether a call is placed. The cell phone searches for a five-digit number known as the System Identification Code assigned to service providers. After selecting a channel, the cell phone identifies itself by sending its programmed codes which identify the phone, the phone's owner, and the service provider. These codes include an Electronic Serial Number (a unique 32-bit number programmed into the phone by the manufacturer), and a Mobile Identification Number, a 10-digit number derived from the phone's number.

The cell site relays these codes to the mobile telecommunications switching office in a process known as registration. The registration process is explained in the Department of Justice's Electronic Surveillance Manual:

Cellular telephones that are powered on will automatically register or re-register with a cellular tower as the phone travels within the provider's service area. The registration process is the technical means by which the network identifies the subscriber, validates the account and determines where to route call traffic. This exchange occurs on a dedicated control channel that is clearly separate from that used for call content (i.e. audio) — which occurs on a separate dedicated channel. * * *
This registration process automatically occurs even while the cell phone is idle. Moving from one service area to another triggers the registration process anew. The cell site can even initiate registration on its own by sending a signal to the cell phone causing the phone to transmit and identify itself.[7]


  1. Mobile Devices: Federal Agencies' Steps to Improve Mobile Access to Government Information and Services, at 1 n.1.
  2. For a description of 2G technologies, see Implementation of Section 6002(b) of the Omnibus Budget Reconciliation Act of 1993, Annual Report and Analysis of Competitive Market Conditions with Respect to Mobile Wireless, including Commercial Mobile Services, Fourteenth Report, 25 FCC Rcd. 11407, 11638-40 (2010) (Fourteenth Mobile Wireless Competition Report).
  3. Connecting America: The National Broadband Plan, at 78.
  4. Id. at 78 (citations omitted).
  5. Id. at 76-78.
  6. The number calculated using FCC data. See Office of Engineering and Technology, FCC, Equipment Authorization Search.[1]. The data represents applications for grants issued for new FCC IDs for equipment class parameters “PCE-PCS Licensed Transmitter held to ear” and “TNE-Licensed Non-Broadcast Transmitter Held to Ear.” Data does not include applications for permissive changes and counts multiple entries for the same FCC ID only once.
  7. In re Application for Pen Register and Trap/Trace Device with Cell Site Location Authority, 396 F.Supp.2d 747, 750-51 (S.D. Tex. 2005)(full-text).


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