ystems all adopt turbo coding as the channel coding technique, support high-order modulation such as 16 QAM, and employ HARQ as the retransmission strategy. As far as other specific techniques are concerned, FuTURE TDD is more like LTE. The same 20-MHz bandwidth is adopted as the maximum bandwidth. Because of the same adoption of MIMO and OFDM techniques, high-frequency efficiency can be achieved-as high as 5 b/s/Hz-for both LTE and FuTURE TDD. They can both support 100- Mb/s transmission and high data rate multimedia services. © 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology 2.3.2 Enhancement of FuTURE TDD to TD-SCDMA Many similarities can be found between FuTURE TDD and TD-SCDMA, but FuTURETDD can outperform TD-SCDMA because it is designed as a Beyond-3G system. The conclusion can also be proved from Table 2.3. The frequency efficiency for FuTURE TDD is 5 b/s/Hz-much higher than for TD-SCDMA. This gives FuTURE TDD the ability to support high data rate multimedia services. The data rate can achieve 100 Mb/s, which can surely satisfy the requirement for all kinds of services in the future. A new multiple access scheme is employed, which is named OFDMA. With the scheme, more users may access the wireless network because different users can be distinguished in both time and frequency domains. Hence, FuTURE TDD can solve the problem of wireless access for a very large number of users. FuTURE TDD was developed after TD-SCDMA; hence, it can obtain more advanced techniques. The employment of MIMO and OFDM tech- niques brings FuTURE TDD better performance. This helps FuTURE TDD support wireless transmission even in environments with high mov- ing speed and large distances from the base station. It can save much power, improve transmission quality, and bring better service experience to users. Evolution Map from TD-SCDMA to FuTURE Due to the difference between TD-SCDMA and FuTURE, the course of evolution will be long. In this section, we will introduce the evolution, where