Mobile Phone Technology

The last version of 3G (3G-HSPA+) technology has squeezed a fast capable network from the 3G mobile phone network. There was still a demand for more speed and more capacity within the network. To do this a new generation of network was implemented that had an advertised speed of 100Mbps. By it's nature 4G LTE is an evolution of the previous 3G-HSPA+ technology. There were a number of potential technologies capable to delivering 4G but the evolution from previous networks was seen as the best solution. The aim of 4G LTE is to achieve higher capacity, reduced latency and more efficient use of the spectrum.

4G LTE is an IP (data) only network with no provision for a separate phone channel. Initially the phone function was covered by the earlier 2G network. Thus to make a phone call the original 4G network would drop the 4G connection and then connect to an available 2G network. This led to early complaints that 4G phones could not make phone calls; caused by the phone not find a suitable 2G network to make the phone call. Even 15 years after the start of the 4G revolution and if VoLTE connection cannot be found the phone will resort to 2G phone calling. You can tell whether the phone is using 4G calling or 2G calling as on 4G calling "VoLTE" image appears on the screen, and you can hear the difference in call quality as well.

Two new frequencies were available for the MNOs to bid for in the introduction of 4G. 800MHz was seen as the 4G for coverage over the country which was backed up by 2.6Ghz to add capacity in conjected areas such as city centre use. The 1800MHz frequency is also used for 4G by EE and Three, as there was spare capacity on this frequency. 1800 was used by EE predecessors for 2G.

As part of the bidding for frequency process, in the UK, one bundle included the additional requirement of a Public Service Obligation - one operator must guarantee a 98% population coverage for 4G. This was purchased by O2.

Typically in a 3G network the communications split the frequency into equal size channels. In 4G there is capability to differ the channel size, and use multiple channels even over different frequencies. A mix and match of the technologies to implement this gives 4G better performance as it used the available frequency more efficiently

4G LTE is an evolution of the previous 3G HSPA+ network. There are 3 key technologies behind 4G :

• SAE - System Architecture Evolution
• OFDM (Orthogonal Frequency Division Multiplexing)
• MIMO (Multiple Input Multiple Output)