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ITU-T Kaleidoscope 2009 Innovations for Digital Inclusion

Dynamic Resource Management for Downlink Multimedia Traffic in OFDMA Cellular Networks. ITU-T Kaleidoscope 2009 Innovations for Digital Inclusion. Dhananjay Kumar Anna University, Chennai, India Email: dhananjay@annauniv.edu. Presentation Outlines. Multimedia Services Multi Carrier Systems

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ITU-T Kaleidoscope 2009 Innovations for Digital Inclusion

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  1. Dynamic Resource Management for Downlink Multimedia Traffic in OFDMA Cellular Networks ITU-T Kaleidoscope 2009Innovations for Digital Inclusion Dhananjay Kumar Anna University, Chennai, India Email: dhananjay@annauniv.edu

  2. Presentation Outlines • Multimedia Services • Multi Carrier Systems • OFDMA System Model • Problem Formulation • Two Stage Rate Adaptive (TSRA) Algorithm • Bandwidth Adaptive (BWA) algorithm • Results & Discussions

  3. Mobile Multimedia Services • Multimedia over Mobile Network • Text • Images • Video • Audio • QoS Support • Dynamic & Efficient Resource Requirements

  4. MPEG-4 video trace (Die Hard III) Frame Size Frame Index Courtesy: Technical University, Berlin : http://www.tkn.tu-berlin.de/research/trace/ltvt.html

  5. Trace File of Some Hollywood Movie Courtesy: Technical University, Berlin : http://www.tkn.tu-berlin.de/research/trace/pub.html

  6. MPEG-4 Advanced Audio Coding Audio quality AAC-LD 64 kbps AAC-ELD 64 kbps AAC-LC 56 kbps CD like Quality (BW>15 KHz) AAC-ELD 32 kbps HE-AAC 20 kbps ULD 80 kbps MP3 64 kbps Wide Band (BW 7 KHz) Speech codec (Speech) Telephone codec Narrow Band (BW 3.5 KHz) Speech codec (Music) 10 20 30 40 50 100 130 Algorithmic delay in ms AAC: Advanced Audio Coding ULD: Ultra-Low-Delay AAC-ELD: Enhanced Low Delay AAC AAC-LD: Low Delay AAC AAC-LC: Low Complexity AAC HE-AAC: High-Efficiency AAC Courtsey: Fraunhofer IIS

  7. Service classification and service parameters Guidelines for evaluation of radio interface technologies for IMT-Advanced Source: Document 8F/TEMP/568

  8. Multi-Carrier Communication in Next Generation Networks • Higher Capacity • Can approach theoretical limit • Easy support for adaptive resource Allocation • The Concept of Sub Channel/Carrier • Ability to combat inherent problems in wireless

  9. Multi Path Propagation Diffraction Reflection Line of sight Scattering Reflection

  10. Channel Response in Freq. Domain |H(f)| f

  11. The Concept of Multi-carrier Power Power Frequency Frequency BS BS

  12. Multi-Carrier Communication Systems • MC-CDMA • Suitable for indoor wireless environment • Fading resistance using frequency diversity • Need for rake receivers • OFDMA • Handling of multipath fading (ISI) • Spectral efficiency • No intra-cell interference (No Cell breathing)

  13. OFDMA System Model User Subcarrier 1 1 Sub carrier and bit allocation scheme (M-QAM) IFFT and parallel to serial Add cyclic prefix 2 Subcarrier 2 Subcarrier N N Allocation information Wireless channel to user k Symbos to bit mapping Su carrier selector FFT and serial to parallel Remove cyclic prefix

  14. Problem Formulation Initial subcarrier allocation: αk is chosen such that 0 ≤ αk < 1 while satisfying the condition To calculate Nmin , we first compute BER of the sub channel. The BER of ith subcarrier using M-QAM can be approximated by.

  15. Problem Formulation cont. The order of modulation M for the ith sub carrier is chosen such that the BER < 10-3. In M-QAM the maximum capacity could be approximated by If Rk is the minimum bit rate needed to support an application k, and Risb is the bit rate supported on the ith sub carrier, then the minimum no of required sub carrier is given by

  16. Problem Formulation cont. Considering L types of applications, the sub carrier selection can be defined as optimization of such that average capacity (bits/second per Hz), Cav represented below is maximum.

  17. Development of TSRA Protocol Rth2 Rth1 Packet/Time unit Time Units

  18. The BWA Algorithm START Initialize Rth1, Rth2, Ri Monitor the change in input data rate (ΔRi) in every tmin duration A Is ΔRi is small Yes No If Ri changes from Rth1 to Rth2 If Ri changes from Rth2 to Rth1 Is Ri centered around Rth1 or Rth2 If Ri fluctuates Rth1≤Ri≤Rth2 No No No Yes Yes Yes Yes Wait for tmin. Same status ? Wait for tmin. Ri at Rth1? Wait for tmin. Is ΔRi>rth? Wait for tmin. Ri at Rth2? A A A A No No No Yes Yes Yes Yes Starts de-allocation & share among ABR & nrt-VBR Vary the modulation order to meet the requirements Assign Mean Value Rti= (Rt1+ Rt2)/2 Allocate from nrt-VBR & ABR till Rti = Ri+Riac Is call disconnected? No Yes END No

  19. Average Capacity

  20. Throughput per OFDM Symbol

  21. Average delay for rt-VBR traffic

  22. Average BER

  23. CONCLUSION Multi-carrier can support future multimedia services The OFDMA based system offers high capacity / efficiency The TSRA algorithm can meet the QoS requirement of high quality multimedia applications while approaching theoretical limit (more than 6b/s/Hz for 128-QAM)

  24. Thank You Very Much

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