Issue link: https://iconnect007.uberflip.com/i/978458
MAY 2018 I PCB007 MAGAZINE 15 works. Following shortly after that were the first European 3G networks in the UK and It- aly, in 2003. While 3G was still being devel- oped, several 2.5G services tried to bring old- er technologies up to speed; however, the lack of speed was the deciding factor, and while technologies like GPRS and EDGE provid- ed improvements over standard 2G, they did not match the speed of newer 3G platforms (Figure 4). 3G really started to change the mobile phone landscape and the higher, more reli- able speeds enabled trans- mission services such as radio, TV and data trans- fer for the first time. With 3G, brows- ing the Internet on a mobile device became possible without waiting an inordinately long pe- riod of time for a web page to load. And, of course, portable phones were getting smaller and lighter (Figure 5). As with 2G, there were incre- mental improvements to 3G, but LTE was the best known and most widely used. Some have stated that LTE meant that it was a lighter version, not including all the goodies of standard 3G (or 4G or 5G for that matter). The fact is that LTE stands for long term evolution and is used with GSM networks. It is generally much faster as long as the net being used is not overloaded. I once read a good description that said, "During rush hour in the city, back roads are sometimes faster than the freeway." So consider LTE as enabling you to take the uncluttered roads when necessary. It seems that a new generation—a new "G"—has been introduced every 10 years or so. True to form, 4G networks came about in 2008 and phones were introduced that could take advantage of the new frequency bands and the higher data rates. According to the ITU, a 4G network requires a mobile device to be able to exchange data at 100 Mbit/sec. The older 3G networks, on the other hand, some - times offer data speeds as slow as 3.84 Mbit/ sec (Figure 6). Per TechTarget, "Although carriers still differ about whether to build 4G data networks using Long Term Evolution (LTE) or Worldwide In- teroperability for Microwave Access (WiMAX), all carriers seem to agree that OFDM is one of the chief indicators that a service can be legiti- mately marketed as being 4G." OFDM is a type of digital modulation in which a signal is split into several narrowband channels at different frequencies. This is more efficient than TDMA, which divides channels into time slots and has multiple users take turns, transmitting bursts or CDMA, which si- multaneously transmits multiple signals on the same channel. The point is that 4G and 4G LTE (depend- ing on which carrier you use) greatly in- creased the speed, the peak upload rate as well as added other modest but meaningful improvements such as adding LAN, wide area network- ing, and better error correction (Figure 6). So here we are in 2018, and we are anticipating the first 5G net- works and 5G- capable smart de- vices. It is expected that Figure 4: Different 3G technologies and their associated speeds. Figure 5: An early easy-to-carry flip phone.