ech- niques can be employed to use subcarriers in a way that minimises inter-cell interference, thereby further reducing the reuse factor. Terrestrial Broadband Wireless Telecommunications Carrier frequencies Figure 10.34 Frequency reuse in LTE systems LTE Advanced Release 10 (2010) of the 36 series of the LTE standard defines further improvements. This standard is known as LTE Advanced and it includes a number of new technologies, including technologies supporting advanced services and applications, and technologies supporting transmission rates of up to 100 Mbps for high mobility and 1 Gbps (downlink) for low mobility. Standardisation of the next generation (5G) has already started for systems which are expected to be rolled out around 2020. Convergence in Mobile Communications Standards There has been significant convergence in the mobile communications standards used around the world over the past three decades. For example, many different 1G analogue mobile com- munications technologies existed. In contrast, there were significantly fewer 2G technologies. By the arrival of 3G systems, there were two principal technologies: W-CDMA and CDMA2000. It appears very likely that in 4G systems there will be one principal technology used around the world, namely LTE. Originally there were many 1G technologies because initial developments in mobile tele- communications occurred independently by different manufacturers in different countries. Manufacturers initially made technology choices based on their own expertise and marketed their devices to telecommunications network operators with little regard for interoperability, either internationally or with devices made by other manufacturers. By the time 2G standards were being developed, a number of forces drove convergence and these included the desire for: interoperability, to enable roaming of mobile devices onto networks operated by different mobile network operators; Broadband Telecommunications Technologies and Management economies of scale by enabling the manufact