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  LTE Training Document  Index 1.Introduction 2.LTE Key feature 3.LTE Network Elements(Architecture) 4.LTE Network Interfaces 5.LTE-Channel   3G LTE evolution Although there are major step changes between LTE and its 3G predecessors, it is nevertheless looked upon as an evolution of the UMTS / 3GPP 3G standards. Although it uses a different form of radio interface, using OFDMA / SC-FDMA instead of CDMA, there are many similarities with the earlier forms of 3G architecture and there is scope for much re-use. LTE can be seen for provide a further evolution of functionality, increased speeds and general improved performance. LTE Introduction WCDMA (UMTS) HSPA HSDPA / HSUPA HSPA+ LTE Max downlink speed bps 384 k 14 M 28 M 100M Max uplink speed bps 128 k 5.7 M 11 M 50 M Latency round trip time approx 150 ms 100 ms 50ms (max) ~10 ms 3GPP releases Rel 99/4 Rel 5 / 6 Rel 7 Rel 8 Approx years of initial roll out 2003 / 4 2005 / 6 HSDPA 2007 / 8 HSUPA 2008 / 9 2009 / 10 Access methodology CDMA CDMA CDMA OFDMA / SC-FDMA In addition to this, LTE is an all IP based network, supporting both IPv4 and IPv6. There is also no basic provision for voice, although this can be carried as VoIP.   3GPP LTE technologies LTE has introduced a number of new technologies when compared to the previous cellular systems. They enable LTE to be able to operate more efficiently with respect to the use of spectrum, and also to provide the much higher data rates that are being required. OFDM (Orthogonal Frequency Division Multiplex):  OFDM technology has been incorporated into LTE because it enables high data bandwidths to be transmitted efficiently while still providing a high degree of resilience to reflections and interference. The access schemes differ between the uplink and downlink: OFDMA (Orthogonal Frequency Division Multiple Access is used in the downlink; while SC-FDMA(Single Carrier - Frequency Division Multiple Access) is used in the uplink. SC-FDMA is used in view of the fact that its peak to average power ratio is small and the more constant power enables high RF power amplifier efficiency in the mobile handsets - an important factor for battery power equipment. MIMO (Multiple Input Multiple Output):  One of the main problems that previous telecommunications systems has encountered is that of multiple signals arising from the many reflections that are encountered. By using MIMO, these additional signal paths can be used to advantage and are able to be used to increase the throughput.
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