ency - Uplink 0.66-1.0 b/s/Hz/cell Cell edge rate - Downlink 0.04-0.06 b/s/Hz/cell Cell edge rate - Uplink 0.02-0.03 b/s/Hz/cell Delay two way <10 ms Connection set up <100 ms Channel bandwidths (MHz) 1.4~20 Duplex modes FDD and TDD 5 MHz 15kHz Frequency Figure 10.30 Resource allocation in an OFDMA-based LTE standard downlink OFDM frames (each 10 ms) 10 Subframes (1 ms) 2 slots (0.5 ms) 7 OFDM symbols Figure 10.31 Division of LTE telecommunications resources in the time domain Broadband Telecommunications Technologies and Management Resource block Resource element 180441 7 OFDM symbols (0.5 s) Figure 10.32 A resource unit and a resource block Table 10.7 LTE specification for transmission rates and delay Bandwidth 1.4, 3, 5, 10, 20 MHz Duplex mode FDD, TDD, half duplex FDD Channel coding Turbo 1/3 Modulation QPSK, 16-QAM, 64-QAM Multiple access scheme DL: OFDMA, UL: SC-FDMA Multiple antenna Table 10.8 Peak throughput calculation for an LTE system with 5 MHz downlink bandwidth allocation Parameter Value Number of bits / symbol (64-QAM) Number of OFDM symbols/slot Number of slots/subframe Number of subframes/frame Number of frames/s Number of subcarriers/5 MHz Total bits/s 25.4 Mbps After MIMO 2x2 50.4 Mbps Assume overhead of 25% 37.8 Mbps Terrestrial Broadband Wireless Telecommunications network IMS service 'Public' IP network Private network Operator managed IP backbone User data LTE GW Signalling E-UTRAN E-node B E-node B E-node B E-node B E-node B Figure 10.33 Resource allocation in the OFDMA-based LTE standard The use of the more efficient access scheme in OFDMA, as well as a wider bandwidth, enables LTE to achieve higher transmission rates compared with W-CDMA. Furthermore, LTE uses an all-IP end-to-end network, which results in a simplified core network architecture and a less costly network roll-out. This is illustrated in Figure 10.33. Case Study 10.3: IEEE 802.16 (WiMAX) Standard With the growth of data communications and the internet, wireless broadband became a desired alternative to fixed xDSL and cable