Case Study: Implementation Aspects of a GFDM-based Prototype for 5G Cellular Communications

1. Case Study: Implementation Aspects of a GFDM-based Prototype for 5G Cellular Communications • Ivan Simões Gaspar • With the Vodafone Chair (Prof. Fettweis) since February 2012 • Studies: Electrical Engineering (M.Sc.) at the National Institute of Telecommunications in Brazil – INATEL • Research area: robust non-orthogonal multi-carrier modulation schemes for future cellular systems • NI RF Roundtable 2012 • December 10-11, 2012, Bristol, UK

2. Motivations for 5G • M2M dominating subscribers • diverse requirements (high and lows) : • data rate, latency, mobility, quality, security • asynchronous and non-orthogonal modulation • Opportunistic use of spectrum • time and frequency agility • accurate sensing • no interferer (filtering) RF roundtable 2012

3. Challenges • RRM flexible fine-grained sharing of fragmented spectrum • CoMP High rate, low latency, interactive video, apps,increased signaling • Wireless Access: • flexible • scalable • content aware • robust • reliable f vast # M2M deviceslow rate / complexity asynchronous access t RF roundtable 2012

4. Our approach • Question the strict synchronism, orthogonality and high out of band radiation of OFDM based systems with the introduction of new non-orthogonal filtered waveforms that carry the data on the physical layer. • Deal with crosstalk and interference with a transceiver structure termed GFDM (Generalized Frequency Division Multiplexing). • Explore the tradeoff of an increased computational complexity at the Base Stations with a more flexible construction of millions of machine type communications (MTC) devices • Proof of concept prototype with a highly scalable implementation on NI’s PXI platform RF roundtable 2012

5. GFDM Transmitter Model Up conversion Filtering Up sampling Mapping M = number of symbols per subcarrier K = number of active subcarriers • generalization of OFDM • 1 up to M symbols per subcarrier • Pulse shaping with circular convolution (block structure - burst) RF roundtable 2012

6. Matrix Model, x=Ad Circular impulse response The A matrix contains all the possible impulse responses of the system RF roundtable 2012

7. First Demo – ‘Player Approach’ Demo Setup Transmit Signals System Parameters RF roundtable 2012

8. First Demo – ‘Player Approach’ • Few weeks after receiving the HW we get a real time signal coming out of the box RF roundtable 2012

9. A Low Complexity Model • Time approach: • up sampling, circular convolution and up conversion • Frequency approach: • DFT, spectrum repetition, windowing and position shift, IDFT RF roundtable 2012

10. A Low Complexity Model zero stuff repetition circ. convolution windowing Subcarrier processing time vs. frequency domain Subcarrier superposition in frequency domain RF roundtable 2012

11. Low Complexity Model (Matrix) RF roundtable 2012

12. Low Complexity Model GFDM Matrix Model GFDM non sparse spectrum GFDM Low Complex OFDM reference RF roundtable 2012

13. LabView Style TX Model RF roundtable 2012

14. Second Demo – Offline TX LabVIEW interactive transmitter (offline) • LabView based implementation in less than 2 months after basic training • Very friendly graphical interface RF roundtable 2012

15. Out of band Radiation GFDM (red curve) vs. OFDM (blue curve) RF roundtable 2012

16. Third Demo – Online TX LabVIEW interactive transmitter (online) • PXI based implementation in less than 6 months • Very friendly RT and FPGA enviroments integration RF roundtable 2012

17. Third Demo – Online TX RF roundtable 2012

18. Current studies (RX) Math model Block Diagram ICI Channel distortions RF roundtable 2012

19. Future directions UHF white spaces RF roundtable 2012

20. Conclusions • Pulse shaped subcarriers can be achieved in GFDM at reasonable computational cost • Out of band radiation in GFDM can outperform OFDM by several orders of magnitude • Outlook • A hardware implementation of the GFDM transceiver and its multi-user case application RF roundtable 2012

21. Thankyou.