ice areas consisting of multiple overlapping cells. 5.4.1 Technologies in Support of 4G Some of the technologies that will be a part of the next generation networks are as follows. OFDM is a digital modulation technique in which one time symbol waveform and thousands of orthogonal waves are multiplexed, which is good for high bandwidth digital data transmission. W-OFDM Wideband OFDM (W-OFDM) enables data to be encoded on multiple high speed radio frequencies concurrently allowing greater security, an increased amount of data being sent and the most efficient use of bandwidth. It enables implementation of low multipoint RF networks that minimise interferences with adjacent networks. This enables independent channels to operate within the same band, allowing the multipoint networks and point-to-point backbone systems to be overlaid in the same frequency band. The next step in the development towards 4G is the separation between uplink and downlink technolo- gies for the transmission path. The modulation technique that holds the most potential for 4G applications is wideband OFDM. Its potential bandwidth is estimated to be as high as 100 Mbps for the capacity of one cell. Wideband OFDM is chosen as a single carrier solution due to the lower complexity of equalisers for high delay spread channels or high data rates. In this, a broadband signal is broken down into multiple narrowband carriers (tones), where each carrier is more robust to the multipath. In order to maintain orthogonality among tones, a cyclic prefix is added. With proper coding and interleaving across frequencies, multipath fading turns into an OFDM system advantage by yielding frequency diversity. OFDM can be implemented efficiently by using fast fourier transforms (FFTs) at the transmitter and receiver. With MIMO, the channel response becomes a matrix. Since each tone can be equalised independently, the complexity of space-time equalisers is avoided. Multipath propagation remains an advantage for a MIMO-OFDM system since frequency selectivity caused 