Weighted OFDMA Time-Frequency Synchronization for Space Solar Power LEO Satellites Networks: Performance and Cost Analysis

Transcription

1 Weighted OFDMA Tie-Frequency Synchronization for Space Solar Power LEO Satellites Networs: Perforance and Cost Analysis Mohsen Jaalabdollahi, Reza Zeavat Michigan Technological University

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3 Cities in the Equator Transission Line Needed 3

4 LEO Satellite Networs 4

5 Ground Contact/Energy Transission Period International collaboration for SSP à Worldwide Ground station ipleentation Total satellite ground contact Total ground contact period with sunlight Average path loss of wireless power transission Difference in ipact coparing SSO LEO, MEO, GEO; Distributed ground station coverage area SSO = Sun-synchronous Orbit low-earth orbit zone MEO = ediu earth orbit GEO = geosynchronous orbit 5

6 LEO Ipleentation Pros Lower altitudes à lower power loss Lower transission power per unit à Less Environental Ipact Higher Nuber of Satellites à Higher reliability Lower Cost of Developent and Launching Cons LEO has to 5ins contact period per ground stations à Multiple Ground Stations Needed à Handoff Process Needed LEO ay use ultiple satellite transission à Synchronization Needed International Cooperation and Unified Policy; Routing or Battery Storage if a cluster is not in ground station field of view; Applications: SSP to reote and local area 6

7 Articles on SSP via LEO Satellite Networs S. T. Guh, S. A. Zeavat and O. Abdelhali, Space-based Solar Power transfer via LEO satellites networ: Doppler Effect Analysis, IEEE Trans. on Aerospace and Electronic Systes, vol. 5, no., Jan. 5. S. T. Guh, S. A. Zeavat, Space solar power orbit design and cost analysis, proceedings Recent Advances in Space Technologies RAST, 5 7 th International Conference on, 6-9 June 5, pp , Istanbul, Turey. S. T. Guh and S. A. Zeavat, Space-based Solar Power via LEO Satellite Networs: Synchronization Efficiency Analysis, proceedings IEEE Aerospace Conference, Big Sy, MT, March 3-9, 3. S. T. Guh, S. A. Zeavat, and O. Abdlehali, Space-Based Wireless Solar Power transfer via a networ of LEO satellites: Doppler Effect Analysis proceedings IEEE Aerospace Conference, Big Sy, MT, March 3-9,. S. A. Zeavat, and O. Abdlehali, An Introduction to Space-Based Power Grids: Feasibility Study, proceedings, IEEE Aerospace Conf., Big Sy, MT, Mar. 6-,.

8 LEO Ipleentation: Direct Transission Multi-Satellite Synchronization? Different Doppler Different distance to ground 8

9 Tie Synchronization s t = s t T τ { τ } K = Tie offsets: s t s t s 3 t s t s t s 3 t Σ s t Σ s t

10 Frequency Synchronization r T t = e j π fc +Δf t Frequency offsets: { Δ } K f =.5.5 s t s t s t s 3 t s t s 3 t Σ s t - Σ s t

11 Idea! Design a proper training wavefor for tie synchronization which Handles ulti-satellite scenario Could be easily detectable OFDMA [] Use the detected wavefor to estiate frequency offset which Handles the unnown channel Ipulse response Coputationally efficient RLS [] [] M. Jaalabdollahi and S. A. R. Zeavat, "Joint Neighbor Discovery and Tie of Arrival Estiation in Wireless Sensor Networs via OFDMA," Sensors Journal, IEEE, vol. 5, pp , 5. [] M. Jaalabdollahi and S. Salari, "RLS-based estiation and tracing of frequency offset and channel coefficients in MIMO-OFDM systes," Wireless personal counications, vol. 7, pp , 3.

12 Outline Syste Model Proposed Technique Tie Synchronization and Weighted OFDMA wavefor Frequency Synchronization Siulation Results Future Wors and Conclusion

13 Outline Syste Model Proposed Technique Tie Synchronization and Weighted OFDMA wavefor Frequency Synchronization Siulation Results Future Wors and Conclusion

14 Syste Model Received signal by target power station at earth or the leader satellite: Frequency offset FO Channel ipulse response CIR Tie offset r T t s t satellite = e Δ jπ f t h t : Training wavefor of the -th s τ + ν t

15 Outline Syste Model Proposed Technique Tie Synchronization and Weighted OFDMA wavefor Frequency Synchronization Siulation Results Future Wors and Conclusion

16 Tie Synchronization Allocating a set of OFDMA subcarriers to the -th satellite: s T s j p = π Δ e p κ ft s, N Where: Δf = NT s is the OFDM subcarrier spacing N s = κ Nuber of allocated sub-carrier

17 Tie Synchronization r :M:+MN Select s, N n/. s,ns N n/. s, N n/. s,ns N n/. s M, N n/. s M,Ns N n/. ˆ = arg ax p κ H τ s r : + N argax argax argax M

18 Tie Synchronization

19 Weighted OFDMA wavefor Increasing N s results high Pea to Average Power Ratio PAPR G PAPR = ax N s s N s =, G PAPR = db N s =, G PAPR = 3dB N s = 4, G PAPR = 6dB N s = 8, G PAPR = 9dB N s = 6, G PAPR = db

20 Weighted OFDMA wavefor Weighted OFDMA wavefor N e w T s s p ft p j p s = Δ, κ π { } PAPR N N w G c c w γ = : arg ax ˆ + = p p N H p w r s w c κ : = PAPR s N s G ax

21 Weighted OFDMA wavefor ˆ = arg ax p κ w s p : + N τ wp H r w s, N n w Ns s,ns N n /w /w Ns.. argax r :M:+MN Select w s, N n w Ns s,ns N n w M s M, N n w M Ns s M,Ns N n /w /w Ns /w M M /w Ns.... argax argax M

22 Outline Syste Model Proposed Technique Tie Synchronization and Weighted OFDMA wavefor Frequency Synchronization Siulation Results Future Wors and Conclusion

23 Frequency Synchronization Tie Synchronization Select the training wavefor RLS based channel Estiation h" ε RLS based frequency offset Estiation

24 Frequency Synchronization RLS based channel estiation iniizes: Where: Linear function respect to RLS based frequency offset estiation iniizes: Where: Non-Linear function respect to = = n n h n C h e ˆ ε λ N j n h s h r e e ˆ ˆ = ε π ε = = n n h n e C ˆ ε λ ε N j n h s h r e r e ˆ ˆ = ε π ε ĥ εˆ

25 Outline Syste Model Proposed Technique Tie Synchronization and Weighted OFDMA wavefor Frequency Synchronization Siulation Results Future Wors and Conclusion

26 Siulation Results Tie Synchronization perforance: MSE K = = τ τ K τˆ Frequency synchronization and Channel estiator perforance: MSE MSE K = = ε h K ε = = h K K ˆε hˆ

27 Siulation Results

28 Outline Syste Model Proposed Technique Tie Synchronization and Weighted OFDMA wavefor Frequency Synchronization Siulation Results Future Wors and Conclusion

29 Future Wors Proposing a frae-based structure for the proposed wavefor in order to enable tie-frequency offset tracing Extend the proposed ethod to handle frequency dispersive channels such as ionosphere layers

30 Conclusion Tie-frequency Synchronization is vital for SSP Weighted OFDM sub-carriers for ToA estiation which handles Multi- satellite scenario Low PAPR Joint CIR and CFO estiation Low coputational Coplexity

31 Than You! Any Question?