LTE and Its Evolution
- 1. LTE AND ITS EVOLUTION By Jeevan Prakash-Mtech(1311EE05)
- 2. Motivation for LTE Need to ensure the continuity of competitiveness of the 3G system for the future. User demand for higher data rates and quality of service. Packet switch optimized system. Continued demand for cost reduction(CAPEX and OPEX) Low complexity.
- 3. LTE Overview Fig1: GSM to LTE Fig: Circuit and packet domains
- 4. LTE evolution Fig3: LTE and its Evolution
- 5. Transmission Technologies Downlink --- OFDMA Uplink--- SC-FDMA Fig4: OFDMA and SCFDMA
- 6. Channel Dependent Scheduling Channel-dependent scheduling in a mobile- communication system deals with the question of how to share, between different users (different terminals), the radio resource(s) available in the system to achieve as efficient resource utilization as possible. Fig5: Downlink channel-dependent scheduling in the time and frequency domains
- 7. ICIC-InterCell Interference Coordination LTE is designed for frequency reuse 1 (To maximize spectrum efficiency), which means that all the neighbor cells are using same frequency channels and therefore there is no cell-planning to deal with the interference issues. There is a high probability that a resource block scheduled to cell edge user, is also being transmitted by neighbor cell, resulting in high interference, eventually low throughput or call drops. Fig6: ICIC
- 8. ICIC- Cont. The LTE specification includes several messages that can be communicated between eNodeBs using the X2 interface. Fig7: X2 and s1 interface
- 9. Hybrid ARQ Hybrid automatic repeat request (hybrid ARQ or HARQ) is a combination of high-rate forward error-correcting coding and ARQ error- control. In practice, incorrectly received coded data blocks are often stored at the receiver rather than discarded, and when the retransmitted block is received, the two blocks are combined. This is called Hybrid ARQ with soft combining
- 10. Multi Antenna Support MIMO is used to increase the overall bitrate. Fig8: Multiple antennas
- 11. Spectrum Flexibility LTE supports both FDD and TDD within a single radio-access technology, leading to a minimum of deviation between FDD and TDD for LTE- based radio access. Half-duplex FDD reduces terminal complexity as no duplex filter is needed in the terminal. Fig9: Frequency- and time- division duplex
- 12. Increased peak data rate, DL 3 Gbps, UL 1.5 Gbps Higher spectral efficiency, from a maximum of 16bps/Hz in R8 to 30 bps/Hz in R10 Increased number of simultaneously active subscribers Improved performance at cell edges, e.g. for DL 2x2 MIMO at least 2.40 bps/Hz/cell.
- 14. Carrier Aggregation To increase the capacity-increase the bandwidth Bandwidth can be extended by carrier aggregation Multiple component carriers are aggregated and jointly used for transmission to/from a single terminal Fig10: Carrier aggregation
- 15. Cont.. Using contiguous component carriers within the same operating frequency band called intra-band contiguous. Fig11: Carrier aggregation-intra and inter bands
- 16. Relaying Relaying implies that the terminal communicates with the network via a relay node that is wirelessly connected to a donor cell using the LTE radio-interface technology. Fig12: Example of Relaying
- 18. References 4G LTE/LTE ADVANCED FOR MOBILE BROADBAND by Erik Dahlman, Stefan Parkvall, and Johan Sköld, Elsevier press,2011 http://www.3gpp.org/technologies/keywords- acronyms/100-the-evolved-packet-core http://www.3gpp.org/technologies/keywords- acronyms/98-lte http://www.3gpp.org/technologies/keywords- acronyms/97-lte-advanced http://3gppltee.blogspot.in/2012/09/what-is-icic- inter-cell-interference.html
- 19. Thank you