BER performance is used in 3G WCDMA standard evolutions as well as the 4G Long Term Evolution (LTE) standard [13, 14]. Similarly, the 256-QAM constellation facilitates transmission of 8 bits per symbol and is used in DSL standards [15]. Case Study 7.2: WCDMA and HSDPA The second generation of mobile tele- phony systems was standardised in the early 1990s. The GSM was one of a number of standards which facilitated digital voice communications. It also specified a nascent data communica- tions capability in the form of short station message service (SMS) [12]. Digital Modulation Voice communications require a fixed bandwidth; analogue voice communications are carried out using a fixed bandwidth, typically 4 kHz, and digital voice communications require a fixed data rate. For GSM, this data rate was approximately 30 kbps. Moreover all users need the same transmission rate irrespective of where they are located with respect to a cellular base station. The third generation partnership project (3GPP) standards were also initially developed to deliver mobile telephony services. The first and second releases of the standards in 1999 and 2001 (Release 99 and Release 4) were mainly focused on the delivery of circuit-switched voice communications, although variable data transmission rates of 384 kbps to 2 Mbps were also specified. Again the standard specifications ensured that all users could equally access voice and data channels irrespective of their position in the wireless network [13]. Data communications however became a significant aspect of Release 5 of the 3GPP standards. These standards took into consideration where a receiver was located with respect to the base station. This was important because if a receiver was close, it could receive the signal from the base station at a high power level and therefore its SNR would be large enough to support high channel capacity. A device located far away from the base station would experience lower power reception and therefore its channel capacity would be low. Higher ord