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Pål Grønsund Hai Ngoc Pham Telenor R&I Simula Research Laboratory 03.04.09

SENDORA Project and Dynamic Spectrum Access in Primary OFDMA Systems. Pål Grønsund Hai Ngoc Pham Telenor R&I Simula Research Laboratory 03.04.09. ~85%. A cognitive radio implements a set of functions. Spectrum Holes. Spectrum occupied by licensed users. Frequency. Power. Radio

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Pål Grønsund Hai Ngoc Pham Telenor R&I Simula Research Laboratory 03.04.09

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  1. SENDORA Project and Dynamic Spectrum Access in Primary OFDMA Systems Pål Grønsund Hai Ngoc Pham Telenor R&I Simula Research Laboratory 03.04.09 ~85%

  2. A cognitive radio implements a set of functions Spectrum Holes Spectrum occupied by licensed users Frequency Power Radio Environment Time Secondary User Transmitted Signal Spectrum Characterization RF Stimuli Spectrum Mobility Primary User Detection Spectrum Sensing Spectrum Sharing Decision Request Spectrum Hole [Figures inspired by Akyildez. I, Milano’08] [Animations by Gronsund, P’09] Channel Capacity Spectrum Decision

  3. This talk will be split into two main parts SENDORA Project Overview Opportunities for Dynamic Spectrum Access in Primary OFDMA Systems

  4. queries on spectrum status reports on spectrum status SENDORA concept consists in studying and developing a "Sensor Network aided Cognitive Radio" technology Primary Network Cognitive Network Wireless Sensor Network

  5. 3 main project objectives are defined • Identify and analyze operational scenarios of the Wireless Sensor Network aided Cognitive Radio technology • Define and simulate WSN aided opportunistic access and dynamic resources allocation strategies for cognitive radios • Design a flexible and reconfigurable architecture, and demonstrate through a proof-of-concept the WSN aided Cognitive Radio technology

  6. Work Package breakdown, and participants WP2 Scenarios, System requirements and definition WP1 Project Management WP8 Dissemination WP3 Sensing WP5 Cooperative Communications WP4 Cognitive Actuation WP6 WSN design WP7 System integration and Demonstration

  7. The selected scenario is “Nomadic broadband in urban and suburban areas” • Wireless broadband will be an important service for users and operators in the future • Most users are stationary when needing mobile broadband • Cognitive radio can offer high bit rates and low costs • Can later be extended towards mobility

  8. A centralized system architecture with a fusion centre is proposed Primary Systems C = Centralized access capabilityS = Sensing capabilityA = Ad hoc capability

  9. Dynamic Spectrum Access (DSA) will enable a secondary system to utilize available spectrum DSA PU (Primary User) SU (Secondary User)

  10. Current Mobile WiMAX profiles uses OFDMA and TDD TDD (Time Division Duplex) OFDMA (Orthogonal Frequency Division Multiple Access)

  11. Scheduling determines how bursts are mapped onto the OFDMA frame Vertical Striping Rectangular Scheduling Horizontal Striping [figures from WiMAX Forum, ns-2 System Documentation]

  12. Ns-2 source code can be modified to output relevant information direction / Connection ID subchannel offset symbol offset burst profile #subchannels #symbols FrameNum: 2410, Burst 4: start=3 (12.054552) numSubchanels=1 subchannelOffset=2 duration=3 :ULCID=3 UIUC=11 FrameNum: 2410, Burst 5: start=3 (12.054552) numSubchanels=1 subchannelOffset=3 duration=3 :ULCID=1 UIUC=11 FrameNum: 2410, Burst 6: start=15 (12.055923) numSubchanels=35 subchannelOffset=0 duration=0 :ULCID=-1 UIUC=14 FrameNum: 2411, Burst 0: start=3 (12.056345) numSubchanels=29 subchannelOffset=0 duration=2 :DLCID=65535 DIUC=2 FrameNum: 2411, Burst 1: start=5 (12.056573) numSubchanels=56 subchannelOffset=0 duration=4 :DLCID=16393 DIUC=7 FrameNum: 2411, Burst 2: start=28 (12.059202) numSubchanels=30 subchannelOffset=0 duration=0 :DLCID=-1 DIUC=14 FrameNum: 2411, Burst 0: start=0 (12.059209) numSubchanels=30 subchannelOffset=0 duration=2 :ULCID=-1 UIUC=1 FrameNum: 2411, Burst 1: start=2 (12.059437) numSubchanels=30 subchannelOffset=0 duration=1 :ULCID=-1 UIUC=2 FrameNum: 2411, Burst 2: start=3 (12.059552) numSubchanels=1 subchannelOffset=0 duration=3 :ULCID=5 UIUC=11 FrameNum: 2411, Burst 3: start=3 (12.059552) numSubchanels=1 subchannelOffset=1 duration=3 :ULCID=4 UIUC=11 FrameNum: 2411, Burst 4: start=3 (12.059552) numSubchanels=1 subchannelOffset=2 duration=3 :ULCID=1 UIUC=11 FrameNum: 2411, Burst 5: start=15 (12.060923) numSubchanels=35 subchannelOffset=0 duration=0 :ULCID=-1 UIUC=14 FrameNum: 2412, Burst 0: start=3 (12.061345) numSubchanels=29 subchannelOffset=0 duration=2 :DLCID=65535 DIUC=2 FrameNum: 2412, Burst 1: start=5 (12.061573) numSubchanels=56 subchannelOffset=0 duration=4 :DLCID=16393 DIUC=7 2 users, Downlink CBR traffic (1500 Bytes, 20 pps)

  13. Vertical striping is used to allocate OFDMA slots in the WiMAX ns-2 simulator

  14. Available capacity can be calculated Frequency (Subchannels) OFDMA Capacity (Subch * Symb) PU1 DL Avail- able PU1 UL DL MAP CAPtot PU2 UL CAPavail Preamble Available PU2 DL PU3 DL UL MAP CAPused Initial Ranging Frame Index Time (Symbols) OFDMA Frame

  15. OFDMA Capacity OFDMA Capacity Frame Index Frame Index Downlink CBR traffic (1500 bytes, 20 pps) for 20 users (Best Effort) BW: 10 MHz DL-UL ratio: 2/3-1/3 47.56 % Occupancy UL : Max OFDMA Capacity 525 (35*15) DL : Max OFDMA Capacity 850 (30*28)

  16. OFDMA Capacity OFDMA Capacity Frame Index Frame Index Uplink CBR traffic (1500 bytes, 20 pps) for 20 users (Best Effort) BW: 10 MHz DL-UL ratio: 2/3-1/3 95.97 % Occupancy UL : Max OFDMA Capacity 525 (35*15) DL : Max OFDMA Capacity 850 (30*28)

  17. Temperature plot for occupancy for all OFDMA frames indicate potential for DSA • Downlink CBR traffic for 20 BE users (20 seconds)

  18. Downlink CBR traffic for 20 BE users (20 seconds) Probability of Occupancy Sub channels OFDM Symbols Occupancy distribution over all the traffic indicates potential for DSA

  19. CBR traffic for 20 BE users (1 sec) UL Capacity (SubCh*Symb) DL Capacity (SubCh*Symb) Frame Index Frame Index The consecutiveness of occupancy on a frame-by-frame basis is important for DSA Downlink Uplink

  20. DL Subframe, DL CBR traffic for 20 BE users (500 ms) Probability of Occupancy Frame Index Slot Index One approach is to derive schemes for probability of occupancy (eg. time dependent occupancy distribution)

  21. DSA In summary, we are characterizing the opportunities for DSA in primary OFDMA systems Capacity, distributions and consecutiveness of available OFDMA spectrum is characterized Derivation of schemes, protocols and systems for DSA in primary OFDMA systems is necessary Questions? Pal Gronsund (pal.gronsund@telenor.com) Hai Gnoc Pham (hainp@ifi.uio.no)

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