 a significant buzz in the mobile market in the mid- to late 2000s, it eventually wilted against competition from the 4G LTE standard. Several reasons have been given, including the fact that as LTE grew from the matrix of GSM/WCDMA standards, the network equipment was backwards compatible and therefore posed a lower risk/cost to incumbent operators. Further reasons include slow call set-up speed, and insuf- ficient support at higher layers for call set-up and data packet transfer. A bigger reason perhaps was the unwillingness of major manufacturers to support multiple standards. Costs of research and development, intellectual property protection and management become too large, and a single global standard became the most efficient way forward. By 2012, the main supporters of WiMAX conceded its unviability. Two modes of LTE standards are now set to become universal technologies for provision of wireless broadband [17]. Case Study Questions What were the motivations behind the development of wireless broadband systems? What was the initial focus of 2G and 3G systems? Why was the TDD market more attractive to WiMAX? What are the costs associated with supporting two standards for operators and manufacturers? Why was LTE successful in defeating WiMAX as a competitor, and was this inevitable? Frequency Reuse for LTE Systems LTE systems are based on OFDMA technology and therefore a combination of FDMA and TDMA. As a result a frequency reuse factor of 1 cannot be possible since a user may be impacted by interference from a neighbouring cell as illustrated in Figure 10.12. Therefore a reuse factor of 3, as shown in Figure 10.18, is a starting operation. In practice, a lower reuse factor may be devised. This is illustrated in Figure 10.34 for a WiMax system [18]. The frequency reuse is 3, however, all subcarriers may be used in the cell centre as these are sufficiently separated from the sources of interference in other cells. In this way the frequency reuse factor can be employed. Moreover, dynamic resource allocation t