How Cell Phones Work

By: Marshall Brain, Jeff Tyson & Julia Layton


For decades, the mobile world has pushed for industry-wide standards to sync up the technology and allow for definable advances. Many see LTE, or Long Term Evolution, as the first real chance at standardization, as many top carriers have signed on to adopt the technology [source: 4G Americas].

LTE is being developed as the 4G standard, which is why you sometimes see "4G LTE" as opposed to simply "4G." 4G could mean support for any speed above 3G; 4G LTE means support for up to 86 Mbps based on specific technology and software infrastructures [source: 4G Americas].


The LTE network is based on Internet Protocol (IP) standards, the kind that delivers Web pages to your computer, and adds voice data to the transmission streams [source: 4G Americas]. It uses a schematic called OFDMA, or Orthogonal Frequency Division Multiple Access, which is similar to the OFDM approach in WiMAX. OFDMA also separates the bits in a single data transmission into multiple subcarriers to increase speed, reassembling it at the destination. The LTE protocol, though, has the added ability to assign particular data paths to particular users on the fly, optimizing the bandwidth available at any given time [source: 4G Americas].

LTE can operate on a wide range of radio frequency bands, which will allow many mobile carriers to switch over to LTE without starting from scratch [source: 4G Americas]. The migration has already begun: 4G LTE is operating in many U.S. and European cities in 2013 [source: Osborne]. It doesn't require a new phone. LTE can operate alongside 2G and 3G networks, and multi-mode phones can access any of them, using LTE where it's available and, say, HSPA where it's not [source: 4G Americas].

Having a multi-mode phone, then, is a huge benefit as LTE towers start popping up around the country and around the world.