New direction of broadband wireless technology

The most important technical challenge for the realization of 4G mobile networks is twofold: (a) to overcome the highly frequency-selective fading channel and (b) to significantly reduce the transmit power from mobile terminals. Recently, it has been shown that the application of frequency-domain equalization (FDE) can take advantage of channel frequency-selectivity and improve the transmission performance of single-carrier (SC) as well as multi-carrier (MC) signal transmissions. Either SC or MC can be used for the downlink (base-to-mobile) to achieve almost the same bit error rate (BER) performance. However, for the uplink (mobile-to-base) applications, SC transmission is more appropriate since it has less peak power. For broadband data transmissions, transmit power reduction is a very important issue. Applying wireless multi-hop technique is a possible solution to this issue. In this paper, we will discuss about some important 4G wireless techniques. Copyright (C) 2007 John Wiley & Sons, Ltd.