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

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

4. 4 This talk will be split into two main parts Opportunities for Dynamic Spectrum Access in Primary OFDMA Systems SENDORA Project Overview

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

7.  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 3 main project objectives are defined

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

9.  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 The selected scenario is “Nomadic broadband in urban and suburban areas”

10. Primary System s C = Centralized access capability S = Sensing capability A = Ad hoc capability A centralized system architecture with a fusion centre is proposed

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

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

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

14. 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 Ns-2 source code can be modified to output relevant information direction / Connection ID symbol offset subchannel offset #subchannels #symbols 2 users, Downlink CBR traffic (1500 Bytes, 20 pps) burst profile

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

16. PU1 DL Initial Ranging Available Avail- able Frame Index PU3 DL PU2 DL Preamble UL MAP DL MAP PU1 UL PU2 UL CAP tot OFDMA Capacity (Subch * Symb) Frequency (Subchannels) Time (Symbols) CAP avail CAP used Available capacity can be calculated OFDMA Frame

17. 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 OFDMA Capacity Frame Index OFDMA Capacity Frame Index DL : Max OFDMA Capacity 850 (30*28) UL : Max OFDMA Capacity 525 (35*15)

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

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

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

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

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

23. 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)pal.gronsund@telenor.com Hai Gnoc Pham (hainp@ifi.uio.no)hainp@ifi.uio.no In summary, we are characterizing the opportunities for DSA in primary OFDMA systems DSA