AIRCOM LTE Webinar 3 - LTE Carriers

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This third webinar discusses the fundamentals of LTE Carriers and how LTE mobiles communicate with the network including what factors affect performance.

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AIRCOM LTE Webinar 3 - LTE Carriers

  1. 1. The webinar will start shortly. AIRCOM LTE Webinar Series: LTE Carriers © 2013 AIRCOM International Ltd
  2. 2. AIRCOM LTE Webinar Series: LTE Carriers © 2013 AIRCOM International Ltd
  3. 3. About AIRCOM AIRCOM is the leading provider of mobile network planning, optimisation and management software and consultancy services. Advise Manage Audit Network Optimise    3       Founded in 1995 14 offices worldwide Over 150 LTE customers Acquired Symena in 2012 Products deployed in 159 countries Comprehensive Tool and technology training portfolio Plan TEOCO offer very complimentary assurance an optimisation solutions as well as an excellent analytics portfolio. Significantly stronger combined offering for customers Find out more at www.aircominternational.com © 2013 AIRCOM International Ltd
  4. 4. About the Presenters     Graham Whyley – Technical Master Trainer AIRCOM Technical Master Trainer since 2005 Currently responsible for all LTE training course creation and delivery Over 20 years of training experience at companies including British Telecom and Fujitsu   4 Gavin Hayhurst – Product Marketing Manager Contact us at training@aircominternational.com © 2013 AIRCOM International Ltd
  5. 5. What's happening in the new year Webinar series 2 – The physical Layer Backhaul design for GSM,UMTS & LTE Part 1 : Calculating the backhaul bandwidth for LTE Spectral efficiency, What affects cell throughput, Physical/Application Rate, Cell edge Spectral efficiency. Dimensioning the S1-U Relay PDCP GTP-U RLC UDP L1 Data Rate In/out of core L1/L2 Part 2 : SDH/PDH IP MAC Basic overview of protocol stack, What is the difference between E1&VC-12, T1 & VC-11 etc. eNode B Part 3 : Capacity and performance monitoring What is the capacity of STM-1, 4, 16 etc. End to end, section & regenerator performance monitoring Part 4 : Protection ADM, RING networks, MESH, Backhauling GSM, UMTS & LTE Part 5 : Best planning practice : How do we carry Ethernet in SDH 5 © 2013 AIRCOM International Ltd
  6. 6. Agenda- LTE Carriers LTE Carriers Relay PDCP RLC UDP MAC RSRP, RSSI, RSRQ GTP-U IP L1 Data Rate In/out of core L1/L2 LTE Carriers  RSRP, RSSI, RSRQ  Frequency-division duplexing(FDD)  Re-Farming  Time-Division Duplexing (TDD) eNode B 6 © 2013 AIRCOM International Ltd
  7. 7. From Last Webiniar 12 subcarriers = 180 kHz Frequency Domain Normal Cyclic Prefix Normal Frame 84 OFDM symbols (12x7) 12 subcarriers = 180 kHz Resource Element 7 symbols = 0.5 ms 2 bits Time Domain 4 bits Extended Cyclic Prefix 6 bits 7 Resource Block represents the basic unit of resource for LTE Resource Block is a grid: 12 subcarriers in the frequency domain (180 kHz) 6 or 7 symbols in the time domain (0.5 s) 72 or 84 Resource Elements per Resource Block Each Resource Element can accommodate 1 modulation symbol, e.g. QPSK, 16QAM, 64QAM Bandwidth 1.4 (MHz) 3 5 10 15 20 6 symbols = 0.5 ms # of RBs 6 15 25 50 75 100 Subcarriers Extended 72 OFDM symbols(12x6) 72 180 300 600 900 1200 © 2013 AIRCOM International Ltd
  8. 8. What are the Reference Signals-Used for? Physical Cell Identity Reference Signals-Used for cell search, channel estimation and neighbour cell monitoring (handover & Cell selection) SINR ave = S I+N I = Iown + Iother Path Loss DLRS SINR Path Loss Traffic SINR Path Loss Control SINR PCI MIB 8 © 2013 AIRCOM International Ltd
  9. 9. So what MCS have I? Look in control Physical Cell Identity (PCI) =20 I am connected I need to handover RRC CONNECTION RECONFIGURATION setup/modify/release Measurements ref signals Physical Cell Identity (PCI) =55 SINR+19dBm SIB’s/RRC messages SINR-4dBm Down Link Bearers QPSK I can now send a measurement report This is a shared channel (PDSCH) Power 41.46 64 bit QAM I am idle I need to do cell selection Lets look at Ref Signals UMTS/GPRS What about 3G 9 I have good LTE coverage but still on 3G. What is the problem. Aircom Trouble shooting course I need parameters. Aircom Parameter training © 2013 AIRCOM International Ltd
  10. 10. You need to understand how LTE operates before changing power. May improve one channel at the expenses of others. What about the Uplink? PATH LOSS Cannot see MIB I have poor RS SINR ave = S I+N I = Iown + Iother PATH LOSS LESS POWER FOR OTHER CHANNELS 10 MORE POWER FOR TRAFFIC © 2013 AIRCOM International Ltd
  11. 11. UE measurements Cell selection/reselection LTE 3G In cellular networks, when a mobile moves from cell to cell and performs cell selection/reselection IDLE SIBParameters for cell selection LTE In handover, it has to measure the signal strength/quality of the neighbour cells & send a report to the network. Event A5. Serving cell becomes worse than an absolute threshold and the neighbouring cells is better than another absolute threshold In LTE network, a UE measures two parameters on reference signal: • RSRP (Reference Signal Received Power) • GSM UE makes the decision based on Handover RRC CONNECTION RECONFIGURATION Serving cell MME Measurement Report A5 RSRQ (Reference Signal Received Quality) 11 neighbouring cell © 2013 AIRCOM International Ltd
  12. 12. UE measurements In LTE network, a UE measures two parameters on reference signal: • RSRP (Reference Signal Received Power) • RSRQ (Reference Signal Received Quality) •Qrxlevmin used for cell selection in 3GPP release 8 •Minimum required RX level in the cell (dBm) Cell selection/reselection IDLE SIB1/3 Parameters for cell selection •Qrxlevmin and Qqualmin used for cell selection from 3GPP release 9 •Minimum required quality level in the cell (dB) 12 Intra Freq Cell Reselection © 2013 AIRCOM International Ltd
  13. 13. Reference Signal Receive Power 12 sub-carriers Antenna 1 Without MIMO RSRP (Reference Signal Receive Power) is the average power of Resource Elements (RE) that carry cell specific Reference Signals (RS) over the entire bandwidth, so RSRP is only measured in the symbols carrying RS 1 ms Reference Signals occupy 8 out of 168 symbols(14x12) 13 © 2013 AIRCOM International Ltd
  14. 14. Reference Signal Receive Power RSRP (Reference Signal Receive Power) is the average power of Resource Elements (RE) that carry cell specific Reference Signals (RS) over the entire bandwidth, so RSRP is only measured in the symbols carrying RS Reference signals are distributed in both the time and frequency domains Used for cell search, channel estimation and neighbour cell monitoring Reference signals reduce the maximum achievable user plane bit rate by occupying a subset of the resource block symbol locations 12 sub-carriers Reference signals similar to CPICH in WCDMA Without MIMO Antenna 1 1 ms Reference Signals occupy 8 out of 168 symbols RSRP measures signal power from a specific sector while excluding noise and interference from other sectors 14 © 2013 AIRCOM International Ltd
  15. 15. Sub channel RSRP (Reference Signal Receive Power) is the average power of Resource Elements (RE) that carry cell specific Reference Signals (RS) over the entire bandwidth, so RSRP is only measured in the symbols carrying Reference Signals 15 © 2013 AIRCOM International Ltd
  16. 16. Reference Signal Receive Power Reference Signal Received Power (RSRP) 16 © 2013 AIRCOM International Ltd
  17. 17. Received Signal Strength Indicator RSSI is effectively a measurement of all of the power contained in the applicable spectrum (1.4, 3, 5, 10, 15 or 20MHz). This could be signals, control channels, data channels, adjacent cell power, background noise, everything. RSSI varies with LTE downlink bandwidth Point of interest 17 © 2013 AIRCOM International Ltd
  18. 18. Reference Signal Receive Quality RSRP provides information about signal strength and RSSI helps in determining interference and noise information. This is the reason, RSRQ (Reference Signal Receive Quality) measurement and calculation is based on both RSRP and RSSI RSRQ is defined as the ratio N×RSRP / (E-UTRA carrier RSSI) 18 © 2013 AIRCOM International Ltd
  19. 19. Reference Signal Received Quality (RSRQ) LOADED UNLOADED RSRQ affected by cell loads. 19 © 2013 AIRCOM International Ltd
  20. 20. Reference Signal Receive Quality Bandwidth 1.4 (MHz) # of RBs 6 Subcarrier s 72 3 5 10 15 20 15 25 50 75 100 180 300 600 900 1200 Point of interest RSRQ = n x RSRP/RSSI RSRQ = 10 log 25 + (-102.77 –(- 82 .71) =13.97 + (-20.06) =-6.09 20 © 2013 AIRCOM International Ltd
  21. 21. Time-Division Duplexing (TDD) Normal / Extended Multicast-broadcast singlefrequency network (MBSFN) is a communication channel defined in Long Term Evolution (LTE). It can deliver services such as mobile TV using the LTE infrastructure 21 Normal Cyclic Prefix 7 symbols = 0.5 ms 12 subcarriers = 180 kHz Frequency-division duplexing(FDD) Normal / Extended 12 subcarriers = 180 kHz Frame Structures Extended Cyclic Prefix 6 symbols = 0.5 ms Time Domain © 2013 AIRCOM International Ltd
  22. 22. 12 subcarriers = 180 kHz Frame Structures 7 symbols = 0.5 ms For LTE, the normal CP length has been set at 4.69 μs, enabling the system to cope with path delay variations up to about 1.4 km. 22 © 2013 AIRCOM International Ltd
  23. 23. Frame Structures 12 subcarriers = 180 kHz Extended Cyclic Prefix Extended cyclic prefix of 16.7 μs for highly dispersive environments. variations up to about 5km 6 symbols = 0.5 ms Time Domain 23 © 2013 AIRCOM International Ltd
  24. 24. Poll What is Qrxlevmin? 1. 2. 3. 4. 24 It is a parameter used for handover. It is the minimum required quality level in the cell (dB) for cell selection Minimum required RX level in the cell (dBm) for handover. Minimum required RX level in the cell (dBm) for cell reselection © 2013 AIRCOM International Ltd
  25. 25. Poll- Answer 4. Minimum required RX level in the cell (dBm) for cell reselection SIB1 Minimum signal strength requirement from SIB1 (actual value = signalled value  2) 25 © 2013 AIRCOM International Ltd
  26. 26. Frequency-division duplexing(FDD) Band 1 receiver transmitter 2110-2170 MHz 1920-1980 MHZ Frequency-division duplexing (FDD) means that the transmitter and receiver operate at different carrier frequencies. E-UTRA Band Bandwidth UL (MHz) Bandwidth DL (MHz) Duplex Mode 1 1920-1980 2110-2170 Bandwidth 1.4 (MHz) 3 5 10 15 20 FDD 6 15 25 50 75 100 Subcarriers 60Mhz # of RBs 72 180 300 600 900 1200 60Mhz FOR LTE REL’8 26 © 2013 AIRCOM International Ltd
  27. 27. Frequency-division duplexing(FDD) 20Mhz receiver Filters are required Filters are required 2110-2130 MHz Type 1: used for the LTE FDD mode systems transmitter 1920-1940 MHZ Duplex is a scheme whereby transmissions may be sent in both directions simultaneously Channel separation between the transmission and reception frequencies must be sufficient to enable the receiver not to be unduly affected by the transmitter signal. Filters are required within the base station and also the handset to ensure sufficient isolation of the transmitter signal without desensitising the receiver. 27 E-UTRA Band Bandwidth UL (MHz) 1 1920-1980 Bandwidth DL (MHz) Duplex Mode 2110-2170 FDD © 2013 AIRCOM International Ltd
  28. 28. Frequency-division duplexing(FDD) 20Mhz 2110-2130 MHz LTE Subframes then consist of two slots 1920-1940 MHZ Channel characteristics different in both directions as a result of the use of different frequencies Requires paired spectrum with sufficient frequency separation to allow simultaneous transmission and reception Type 1: used for the LTE FDD mode systems 28 © 2013 AIRCOM International Ltd
  29. 29. Frequency-division duplexing(FDD) E-UTRA Band Bandwidth UL (MHz) Bandwidth DL (MHz) Duplex Mode 1 1920-1980 2110-2170 FDD 2 1850-1910 1930-1990 FDD 3 1710-1785 1805-1880 FDD 4 1710-1755 2110-2155 FDD 5 824-849 869-894 FDD 6 830-840 875-885 FDD 7 2500-2570 2620-2690 FDD 8 880-915 925-960 FDD 9 1749.9-1784.9 1844.9-1879.9 FDD 10 1710-1770 2110-2170 FDD 11 1427.9-1452.9 1475.9-1500.9 FDD 12 698-716 728-746 FDD 13 77-787 746-756 FDD 14 788-798 758-768 FDD 29 Europe: Band 7: The 2.6 GHz auctions have been running in a few countries Band 8:is currently used mostly by GSM. The band is attractive from a coverage point of view due to the lower propagation losses. © 2013 AIRCOM International Ltd
  30. 30. Frequency-division duplexing(FDD) E-UTRA Band Bandwidth UL (MHz) Bandwidth DL (MHz) Duplex Mode 1 1920-1980 2110-2170 FDD 2 1850-1910 1930-1990 FDD 3 1710-1785 1805-1880 FDD 4 1710-1755 2110-2155 FDD 5 824-849 869-894 FDD 6 830-840 875-885 FDD 7 2500-2570 2620-2690 FDD 8 880-915 925-960 FDD 9 1749.9-1784.9 1844.9-1879.9 FDD 10 1710-1770 2110-2170 FDD 11 1427.9-1452.9 1475.9-1500.9 FDD 12 698-716 728-746 FDD 13 77-787 746-756 FDD 14 788-798 758-768 Band 8:is currently used mostly by GSM. The band is attractive from a coverage point of view due to the lower propagation losses. FDD 30 Supported Channels (non-overlapping) E-UTRA Band Downlink Bandwidth 1 2 3 4 5 6 7 8 60 60 75 45 25 10 70 35 Channel Bandwidth (MHZ) 1.4 42 53 32 17 25 3 20 23 15 8 11 5 12 12 15 9 5 2 14 7 10 6 6 7 4 2* 1* 7 3* 15 4 4* 5* 3 X 4 - 20 3 3* 3* 2 X 3* - GSM Bandwidth Available © 2013 AIRCOM International Ltd
  31. 31. Any questions? 31 © 2013 AIRCOM International Ltd
  32. 32. Time-Division Duplexing (TDD) TDD means the transmission and reception occur on the same frequency Same frequency E-UTRA Band E-UTRA Band Up Bandwidth UL (MHz) Up Bandwidth DL (MHz) Down Down Duplex Mode 33 1900-1920 1900-1920 TDD 34 2010-2025 2010-2025 TDD 35 1850-1910 1850-1910 TDD 36 1930-1990 1930-1990 TDD 37 1910-1930 1910-1930 TDD 38 2570-2620 2570-2620 TDD 39 40 1880-1920 2300-2400 1880-1920 2300-2400 TDD TDD 32 Down Down Down TDD in unpaired spectrum, whereby the same frequency channel is used for both downlink and uplink communication Duplex Mode 1920-1980 2110-2170 FDD 2 Special Bandwidth DL (MHz) 1 Down Bandwidth UL (MHz) 1850-1910 1930-1990 FDD 3 1710-1785 1805-1880 FDD 4 1710-1755 2110-2155 FDD 5 824-849 869-894 FDD 6 830-840 875-885 FDD 7 2500-2570 2620-2690 FDD 8 880-915 925-960 FDD 9 1749.9-1784.9 1844.9-1879.9 FDD 10 1710-1770 2110-2170 FDD 11 1427.9-1452.9 1475.9-1500.9 FDD 12 698-716 728-746 FDD 13 77-787 746-756 FDD 14 788-798 758-768 © 2013 AIRCOM International Ltd FDD Down
  33. 33. Time-Division Duplexing (TDD) While FDD transmissions require a guard band between the transmitter and receiver frequencies. Down E-UTRA Band Bandwidth UL (MHz) Bandwidth DL (MHz) Duplex Mode 1 1920-1980 2110-2170 FDD UP Down TDD schemes require a guard time or guard interval between transmission and reception. This must be sufficient to allow the signals travelling from the remote transmitter to arrive before a transmission is started and the receiver inhibited. DELAY Down Large guard period will limit capacity. Down 33 Special Up Up Down Down Special Down TDD is not normally suitable for use over long distances as the guard time increases and the channel efficiency falls. Down Down Down © 2013 AIRCOM International Ltd
  34. 34. Type 2 LTE Frame Structure The 10 ms frame comprises two half frames, each 5 ms long. The LTE half-frames are further split into five subframes, each 1ms long One radio frame = 10ms DwPTS carries downlink control channel – scheduling and control information UpPTS used for PRACH and sounding reference signal One half frame = 5ms Down Special Up Up Down Down Down Down Down The sub-frames may be divided into Standard sub-frames or Special sub-frames. In the case of the 10 ms periodicity, the special sub-frame exists in the first half frame only 34 Down Special Downlink Pilot Time Slot, DwPTS Uplink Pilot Time Slot, UpPTS Guard Period © 2013 AIRCOM International Ltd
  35. 35. Type 2 LTE Frame Structure • When switching from DL to UL a guard period is inserted between DwPTS and the UpPTS field. • Guard period depends on the propagation time • Duration of the Guard period depends on cell size • The fields are individually configurable in terms of length, although the total length of all three together must be 1ms Down Special Up Up Down Special Downlink Pilot Time Slot, DwPTS Uplink Pilot Time Slot, UpPTS Down Down Down Down Down Every UE is informed by the enodeB as to when it must start Transmitting. The greater the distance the earlier the UE starts transmitting. The TA prevents conflicts when switching from the uplink to downlink Guard Period 35 © 2013 AIRCOM International Ltd
  36. 36. Type 2 LTE Frame Structure Frame 0 Frame 1 Frame 5 Frame 6 Down Special Up Up Up Down Special Up Up Up Down Special Up Up Down Down Special Up Up Down Down Special Up Down Down Down Special Up Down Down Down Special Up Up Up Down Down Down Down Down Down Special Up Up Down Down Down Down Down Down Down Special Up Down Down Down Down Down Down Down Down Special Up Up Up Down Special Up Up Down Frame 0 and frame 5 (always downlink in TDD) Frame 1 and frame 6 is always used as for synchronization in TDD Frame allocation for Uplink and Downlink is settable in TDD 36 © 2013 AIRCOM International Ltd
  37. 37. preamble formats When we talk about the cell size, we usually think of RF coverage first. The cell radius is also related to the parameter configuration for the random access procedure There are 5 PRACH preamble formats formats 0 to 3 applicable to FDD and TDD format 4 is only applicable to TDD (short preamble ) 37 © 2013 AIRCOM International Ltd
  38. 38. Next Topic Cell Selection Part2 System Information (SIB’s) Cell Selection Part1 Handover Part2 Handover Part1 Comparison between GSM, UMTS & LTE PDCCH &DCI Formats PCI Planning Basic overview of LTE radio Coverage Comparison of LTE Release 8, 9 &10 Increasing coverage & Capacity in LTE RRC Signalling UE measurement reports Attach Procedure NAS Signalling Resource Allocation Type LTE Protocols – UE & eNode B LTE Parameters Designing High capacity cells 38 © 2013 AIRCOM International Ltd
  39. 39. In Closing  Thank you for attending  Webinars webpage – keep up to date and register to receive email alerts on new webinars http://www.aircominternational.com/Web inars.aspx 39 © 2013 AIRCOM International Ltd

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