mplitude modulation). In the work item phase, the supported modulation scheme for data transmission was changed to QPSK, 16 QAM, and 64 QAM (optional). 6.3 Radio Access Techniques The basic uplink transmission technique is single-carrier transmission with cyclic prefix to achieve uplink interuser orthogonality and to enable efficient frequency domain equalization at the receiver side. The transmitter and receiver structure for SC-FDMA transmission is shown in Figure 6.3. An SC-FDMA structure is identified by the insertion of DFT spreading and inverse discrete Fourier trans- form (IDFT) despreading at the transmitter and receiver, respectively. From this © 2009 by Taylor & Francis Group, LLC Table 6.1 Parameters for LTE Uplink Based on the Study Item Transmission BW (MHz) Subframe duration 0.5 ms 0.5 ms 0.5 ms 0.5 ms 0.5 ms 0.5 ms Subcarrier spacing 15 kHz 15 kHz 15 kHz 15 kHz 15 kHz 15 kHz Sampling frequency (MHz) 15.36 23.04 30.72 Long block FFT size Long block number of occupied subcarriers Short block FFT size Short block number of occupied subcarriers CP length (us/sample) (3.65/7) X 7, (3.91/15) X 7, (4.04/31) X 7, (4.1/63) X 7, (4.12/95) X 7, (4.13/127) X 7, (7.81/15) X 1ª (5.99/23) X 1 (5.08/39) X 1 (4.62/71) X 1 (4.47/103) X 1 (4.39/135) X 1 a (x1/y1) X n1, (x2/y2) X n2 means (x1/y1) for n1 reference signal or data blocks and (x2/y2) for n2 reference signal or data blocks. © 2009 by Taylor & Francis Group, LLC Single-Carrier Transmission for UTRA LTE Uplink 0.5 ms LB #2 LB #3 LB #4 LB #5 LB #6 Figure 6.1 LTE uplink subframe structure with two short blocks [6]. implementation structure, SC-FDMA is also known as DFT-spread (DFT-S) OFDM, which is a form of the single-carrier transmission technique where the signal is generated in the frequency domain. The DFT spreading combines parallel M-PSK/M-QAM symbols to form an SC-FDMA symbol. To formulate the DFT-S system, we can start by defining Sm as the mth trans- mitted symbol at the output of an equivalent OFDM system. The modulator con- verts the random bit str