nched by 3GPP. It began in 2004 and aims to accompany a brand new standard to satisfy the requirements for the next 5-10 years. After the study item and work item, one version for such a system has been worked out. TDD and FDD modes are supported. It takes MIMO, OFDM, etc. to bring to the system the ability to raise data rates as high as 100 Mb/s. It can be seen as a system midway between 3G and 4G systems. The two standards support TDD mode; hence, it is necessary to make a comparison between them and FuTURE TDD. © 2009 by Taylor & Francis Group, LLC Evolution from TD-SCDMA to FuTURE Table 2.3 Comparisons of TD-SCDMA, LTE TDD, and FuTURE TDD Systems Aspects TD-SCDMA LTE TDD FuTURE TDD Duplex Multiple access TDMA, CDMA TDMA, OFDMA TDMA, OFDMA Bandwidth 5 MHz 1.4-20 MHz 20 MHz Peak data rate 2 Mb/s 100 Mb/s 100 Mb/s Frequency 0.4 b/s/Hz 5 b/s/Hz 5 b/s/Hz efficiency Antenna Smart antenna configuration Supported services VolP, basic VolP, high data VolP, high data multimedia rate multimedia rate multimedia services, etc. services services Channel coding Turbo coding Turbo coding Turbo coding Modulation QPSK, 8 PSK, QPSK, 16 QAM, 16 QAM 16 QAM 64 QAM MIMO technique Beam forming CDD, STBC, V-BLAST precoding Retransmission 2.3.1 Similarities among TD-SCDMA, LTE TDD, and FuTURE TDD The FuTURE TDD system can be seen as an evolution system for TD-SCDMA. Because the same advanced techniques are adopted as in LTE, they exhibit the same transmission ability. The three systems have much in common and are shown in Table 2.3, in which the main technical configurations can be found. From Table 2.3, we can find the similarities among all the systems. From the basic aspects, they can all support TDD mode; hence, the advantages of TDD (such as flexible frame structure, high efficiency, and flexible frequency band uti- lization) can be obtained when one of the systems is employed. The three systems can all support TDMA when a multiple access scheme is concerned. On the other hand, we investigate some specific techniques. The three s