Cognitive Radio Solutions Beyond DSA MobiCom 2011
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The document discusses cognitive radio technology, emphasizing the need to move beyond traditional dynamic spectrum access (DSA) by utilizing a layered cognitive approach that includes spectrum sensing, spatial processing, and interference mitigation. XG Technology highlights the importance of optimizing spectrum utilization and adapting communication parameters to enhance throughput while minimizing interference. The future of cognitive networks necessitates advanced features such as real-time link optimization and intelligent modulation adaptation for improved performance.
Cognitive Radio Solutions Beyond DSA MobiCom 2011
- 1. “Cognitive Radio Solutions: Moving Beyond DSA” MobiCom 2011 Rick Rotondo, xG Technology The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 1 www.xgtechnology.com
- 2. Cognitive Technology ► Cognitive radio is a paradigm for wireless communication in which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users. Cognitive techniques have been almost exclusively focused on DSA (running away from interference) The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 2 www.xgtechnology.com
- 3. White Spaces? White Spaces Is there such a thing as Active Jamming – Black Spaces White Spaces??? No! it is all gray space to some degree (or worse!) Heavy use – Dark Gray Spaces Average Use – Light Gray Spaces Getting TIME Very Light Use – Off-White Spaces hard to find… Unused Spectrum – White Spaces The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 3 www.xgtechnology.com
- 4. Traditional view of Cognitive Radios ► Able to identify spectrum that is not being used ► Dynamically tunes to those frequencies (within 30 ms) ► Instantly find other spectrum if interference is detected ► Adapt power, modulation, channel plan, network protocol, etc. ► Dynamically maximize throughput (or range) and minimize interference to other devices The Focus on running away from interference (DSA) does a poor job of optimizing all available spectrum resources i.e. Gray/Black Spaces The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 4 www.xgtechnology.com
- 5. xG’s take on Cognitive Radios ► Able to identify spectrum that is not being fully used ► Dynamically tunes to those frequencies (within 30 ms) ► Mitigate interference to the extent possible to extend “dwell time” on the current frequency ► Employ DSA techniques if interference is overwhelming and performance falls below set thresholds ► Adapt power, modulation, channel plan, network protocol, etc. ► Dynamically maximize throughput (or range) and minimize interference xG radios dynamically optimize spectrum utilization through use of all available spectrum resources The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 5 www.xgtechnology.com
- 6. xMax Cognitive Technology xMax Layered Cognitive Approach: – Spectrum sensing: Interference based detection of transmitters. – Spatial processing: MIMO technologies allow resistance to interferers. Optimize SNR using multiple antenna processing. – Spectrum sharing: Able to operate in crowed shared spectrum (ISM UNI II etc.). Detect interferers, mitigate them, or avoid them by changing operating parameters or frequencies. – Spectrum management: Capture the most available spectrum. Terminals and Base Station can change operating frequencies dynamically. – Spectrum mobility: Use spectrum dynamically. Mobile user stations and base stations can decide to change bands where they operate. The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 6 www.xgtechnology.com
- 7. xMax Interference Processing ► Dependably operate on “gray and black spaces” ► Mitigate narrow/wideband, burst/continuous interference. Short bursts of tens/hundred of microseconds typical to cordless phones and other frequency hoppers are removed by identifying the location of error in the time T domain and applying xMax adaptive interference error I correction. M E Longer bursts of several hundred microseconds and longer are removed by spatial multi-antenna, multi- algorithm error processing. Frequency The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 7 www.xgtechnology.com
- 8. xMax Interference Processing ► Spatial processing to remove interference. • xMax samples the arriving RF wave front using 4 antennas. • Interferers can be located by position • Algorithms can be used in the receive chain to mitigate this energy • The xMax system sends known training signals that are measured and used to calibrate the receivers xMax • Spatial processing removes interference that is longer than 800 microseconds. • Shorter interference is removed by redundant coding. The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 8 www.xgtechnology.com
- 9. xMax Interference Processing ► Multi-layer interference mitigation system. Select correctly decoded data based on Receiver algorithm 3 CRC. Receiver algorithm 1 (Time diversity, (MRC) nonlinear combining) Receiver algorithm 2 Receiver algorithm 3 (Spacial projection) (Time diversity, nonlinear combining) The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 9 www.xgtechnology.com
- 10. xMax Interference Processing ► Redundant coding to remove burst interference. Data is Interference randomly Error free symbols Transmitted destroys OFDM symbols. are identified twice. Error free version is reassembled How do we know what pieces of a received signal are erroneous before error correction coding and CRC? With 20 redundant pieces there are 1048576 possible ways to assemble them. Not feasible unless we can identify interference symbol by symbol. The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 10 www.xgtechnology.com
- 11. xMax Interference Processing ► How do we tell what received bits are interfered with? (If we know exactly what bits are wrong we could just invert them!) 6 x 10 1.8 80µs error burst. 1.6 1.4 xMax calculates estimate of OFDM 1.2 symbol being interfered based on statistics 1 computed for the whole data packet. 0 20 40 60 80 100 120 6 x 10 2 By computing statistics for two redundant packets the system can assemble an error 1.5 free packet. It is like an error correction 1 coder on top of error correction coder telling what pieces of the signal the coder should use. 0.5 0 20 40 60 80 100 120 The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 11 www.xgtechnology.com
- 12. xMax Interference Processing Simulation Results 7 6 5 4 3 1.5 2 1 0.5 1 0 0 10 20 30 40 50 60 70 80 90 100 0 0 10 20 30 40 50 60 70 80 90 100 1.4 MHz wide xMax with GSM- 1.4 MHz wide xMax signal after like jammer. Spatial processing. Xmax OFDM BER 0 Xmax OFDM BER 0 10 10 -1 -1 10 10 -2 -2 10 10 BER -3 BER -3 10 10 BPSK -4 QPSK -4 BPSK 10 10 16QAM QPSK 64QAM 16QAM -5 THEOR. 16QAM -5 64QAM 10 10 THEOR. QPSK THEOR. 16QAM THEOR. QPSK -6 -6 10 10 -4 -2 0 2 4 6 8 10 12 14 -4 -2 0 2 4 6 8 10 12 14 SNR SNR The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 12 www.xgtechnology.com
- 13. xMax Overview VoIP CORE POTS calling SMS service xMax Wireless Network xMSC Public or Private Internet Wi-Fi Network SMS server xMod is a mobile xMSC has COTs seamless bridge equipment for between WiFi and xAPs provide wired network Smart Phones, xMax networks network to xMax management, Laptops or any network conversion. firewall , SIP device with WiFi They can be vehicle Proxy, and SMS can connect to the or tower mounted. server xMod xAPs are Ethernet IP connected. WiFi Network xMax Cognitive Radio Network (C-RAN) Core Network Public Network The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 13 www.xgtechnology.com
- 14. Beyond DSA Summary ► Dynamic Spectrum Access (DSA) is a key aspect of CR ► But Cognitive Networks Must Leverage More Than DSA! – Parallel Receiver Processing Chains (MIMO) – Interference Mitigation Algorithms – Adaptive Antennas, Beam Forming – Adaptive Architecture (Point to Multipoint, Mesh, etc.) – Application Aware QoS (VoIP, Throughput, Latency, Priority) – Automatic & Dynamic Channel Planning – Intelligent Modulation Adaptation – Real-time Link Optimization – Transmit Power Adjustment The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 14 www.xgtechnology.com
- 15. Thank You The information presented herein is confidential and subject to change without notice. xG® and xMax® are registered trademarks of xG Technology, Inc. Copyright 2010, All Rights Reserved. 15 www.xgtechnology.com