41 Symbol Transmission verses Time OFDM Symbol Number Pre amble Sub Channel

41 symbol transmission verses time ofdm symbol number

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41 Symbol Transmission verses Time OFDM Symbol Number Pre- amble Sub Channel Number 0 . . . . . . . n Each OFDM symbol consists of n sub-carrier symbols k+1 k+2 k+3 k+4 k+5 k+6 k+7 k+8 k+9 k+10 k Transition Gap Transition Gap DL- Map DL Burst UL Burst 802.16e can use time-division or frequency- division multiplexing between the up and down-link bursts.
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A G R E A T E R M E A S U R E O F C O N F I D E N C E © Copyright 2007-2008 Keithley Instruments, Inc. 42 Transmitting Multiple Symbols Simultaneously I Q
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A G R E A T E R M E A S U R E O F C O N F I D E N C E © Copyright 2007-2008 Keithley Instruments, Inc. 43 Dynamic Symbol Map
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A G R E A T E R M E A S U R E O F C O N F I D E N C E © Copyright 2007-2008 Keithley Instruments, Inc. 44 The Physical Channels are Different from the Logical Channels Physical sub-channels are changed every symbol using a PN sequence. -fn 0 +fn
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A G R E A T E R M E A S U R E O F C O N F I D E N C E © Copyright 2007-2008 Keithley Instruments, Inc. 45 Link Characteristics – Summary Distance Close – Far away High Data Throughput (QAM) More Sub-channels used Low Data Throughput (QPSK) Less Sub-channels used Users Many – Few
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A G R E A T E R M E A S U R E O F C O N F I D E N C E © Copyright 2007-2008 Keithley Instruments, Inc. 46 demo WiMAX Measurements
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A G R E A T E R M E A S U R E O F C O N F I D E N C E © Copyright 2007-2008 Keithley Instruments, Inc. 47 WiMAX Summary This is metropolitan area networking – internet to your home, office or car. Implies one of the 802.16 Standards Very similar in concept to 802.11, but the demands of multiple simultaneous users (possibly mobile) make the implementation much more complex. Uses scheduled transactions to ensure all paying users get access. You can get frozen out with WiFi. Stands for: W orldwide I nteroperability for M icrowave Ac cess • SOFDMA (Scalable OFDM Multiple Access) • SOFDMA interoperates with OFDMA, but requires new equipment. • Adds MIMO The current version of the standard, upgraded to include mobile wireless. 802.16e-2005 • OFDMA (OFDM multiple access) • 2-11 GHz (no regulatory approval above 5.9 GHz) • Practical rate: 10 Mbps over 2 km Fielded system for fixed-point access (to the home or office) 802.16-2004 (aka 802.16d) Means 802.16
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A G R E A T E R M E A S U R E O F C O N F I D E N C E © Copyright 2007-2008 Keithley Instruments, Inc. 48 OFDM/A to MIMO MIMO uses multiple transmitters and receivers that are modulated with OFDM/A. Both WLAN (802.11n) and WiMAX (802.16e) have MIMO configurations
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A G R E A T E R M E A S U R E O F C O N F I D E N C E © Copyright 2007-2008 Keithley Instruments, Inc. 49 Spectrally Efficiency – SISO Æ MIMO Bits/Second/Hz 6.0 4.0 2.0 0.5 WLAN 802.11n GSM WLAN 802.11a/g W-CDMA HSDPA
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A G R E A T E R M E A S U R E O F C O N F I D E N C E © Copyright 2007-2008 Keithley Instruments, Inc.
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  • Spring '16
  • WiMAX, Keithley Instruments

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