Presentation on theme: "Dirty RF Impact on Interference Alignment"— Presentation transcript:
1 Dirty RF Impact on Interference Alignment Per Zetterberg
2 Outline Goal Approach Interference-alignment and CoMP Implementation ResultsImpairment-modeling (closening the gap theory-simulation)Conclusion
3 Goal New interesting and challenging techniques Assumption: Results are general.Robust approachesImpairment-modelingFEREVMSINRMatch!DetailedsimulationTestbedMeasurements(USRP)Channels
4 Approach Impairment model PC Basic simulation Test-bed Measurements (USRP)Impairment-modelingBasicsimulationImpairment modelTransmitterSpectrum analyzerPC
5 Interference alignment Cadambe/Jafar, ”Interference Alignment and Degrees of Freedom of the K-User Interference Channel”,IEEE Trans, Information Theory 2008.K-transmitters and K-receivers, K-links:K/2 simultaneous interference-free links.Requires coding over multiple channel realizations.Global channel knowledge required.
6 Interference-alignment incarnations In frequency-domain: Something new –will be studied later. In antenna-domain: Co-ordinated beam-forming.
16 Phase-noise Modeled as additive noise + CPE BPFLNALPFA/DCPE: Slowly varying between symbolsy 𝑡 = exp 𝑗 𝜃 𝑡 𝑠 1 𝑡 + 𝑛 1 (t)R. Corvaja, E. Costa, and S. Pupolin, “M-QAM-OFDM system performance in the presence of a nonlinear amplifier and phase noise, IEEE Trans. Comm
18 IA ResultsWithoutimpairmentmodelWithimpairmentmodel
19 Conclusion: What will be answered? How much worse is IA practice than in theory?What practical impairments need to be modeled?(==> can lead to improved robust designs)Is IA still worthwhile with impairments compared to base-lines ?Other outputsSoftware environments that can be re-used (commodity hardware)Increased understanding of software and hardware issues and implementations in our research community and our PhDs in particular.Course-work for the above.
20 Structure of modelRXTXTXRXChannelTX- impairmentRXTX
22 The 4Multi Software FrameWork (Multi-Antenna, Multi-User, Multi-Cell, Multi-Band)Send data in small bursts (relaxes computational load)Nodes synchronized by external trigering (PPS)The implementor (basically) only need to program three functionsnode::init, node::process and node::end_of_run.Simulate the system using “simulate” generic function.Everything that can be compiled with gcc can run (e.g IT++)Toolbox with coding&modulation.Store _all_ received signals for post-processing.Vision:“The coding should be as easy as performing ordinary(but detailed) desktop simulations”