Same frequency, same time, ?double wireless speeds. Today, self-interference makes it impractical to send and receive at the same time on the same frequencies. Testing at Deutsche Telekom and SK Telecom suggests Moore's Law is bringing enough processing power to change that. (pr below.) They are working with Kumu Networks, a spinoff from the lab of Stanford's Philip Levis. Their extraordinary advisory board gives them extra credibility.
Research on Full Duplex is hot. An article by Sabharwal et. al. lists 141 papers (below.) At Columbia, Harish Krishnaswamy has developed chips. At a Cambridge Wireless meeting, David Lister of Vodafone concluded, "We can consider the problem of self-interference cancellation as solved. Now is the time to consider system requirements and assess the use cases. There are still major challenges to overcome."
Joel Brand of Kumu is confident. "By the second half of 2016 we could ship full-duplex solutions for infrastructure applications where the requirements are a bit more relaxed than in a mobile phone." WISP backhaul would be a natural niche for this kind of product.
Some are skeptical about the potential to double performance in the real world.
Xiufeng Xie and Xinyu Zhang of the University of Wisconsin believe "While it is tempting to believe that full-duplex can double wireless capacity, this paper disproves the perception through asymptotic analysis and network optimization. Indeed, for a single link, full-duplex may have a capacity gain of 2 over half-duplex, but in large-scale wireless networks, spatial reuse and asynchronous contention effects significantly undermine the actual benefits of full-duplex."
Brand thinks performance degradation will rarely be important in practice. "There are some improvements that need to be made at the MAC layer in order to prevent phone-to-phone interference on the broadcast channels in an environment where everything is on a single frequency. There are plenty of proposals in academia (one actually from Phil Levis) and in the industry (check some of the work that has been done around High Efficiency WiFi) to address that. It will result in doubling the spectral efficiency of what existing systems can provide, or at least come very very very close to that."
The best engineers I know expect wireless capacity to increase fifty times or more. Full Duplex may be one of the tools.
Thanks to Telecoms.com for pointing me to this story. Here are some of the primary sources.
- Philip Levis, Professor of EE and CS at Stanford University, Co-Founder
- Sachin Katti, Professor of EE and CS at Stanford University, Co-Founder
- Nick McKeown, Professor of EE and CS at Stanford University
- Bernd Girod, Professor of EE and CS at Stanford University
- Andy Rachleff, Alumni Partner at Benchmark Capital, Faculty Member at Stanford GSB
- Jon Peterson, Fellow at Neustar, Member of the Internet Architecture Board
- Sanjit Biswas, CEO, Meraki Inc.
- Guru Parulkar, Consulting Professor, Stanford University
- Arogyaswami Paulraj, Professor Emeritus of EE, Stanford University
- New Enterprise Associates [Forest Baskett, Ron Bernal]
- Khosla Ventures
- Third Point LLC [Rob Schwartz]
– SK Telecom (NYSE:SKM) announced today that, together with Kumu Networks, it will demonstrate a robot traffic officer using In Band Full Duplex (IBFD) technology at the World IT Show 2015 (WIS), to be held in Seoul, Korea from May 27 to 30.
IBFD is being highlighted as one of the key pre-5G technologies as it enables simultaneous in-band uplink and downlink communication by cancelling signal interference in real time, thus significantly enhancing the spectral efficiency.
As the current networks cannot transmit and receive signals at the same time on the same channel, mobile operators have to choose either FDD or TDD to enable communication between base stations and handsets.
At this year’s WIS, SK Telecom and Kumu Networks will showcase a new Robocop tasked with traffic management in the pre-5G network environment applied with the IBFD technology. Built with a camera, microphone and multiple sensors, the Robocop not only mirrors human movement without latency, but also transmits/receives multimedia data – both video and audio – to/from the control center in real time
As the demonstration shows in detail how 5G networks can wirelessly transmit and receive massive amounts of data in a real-time manner, it is expected that 5G, once realized, will enable flawless provision of innovative IoT services.
SK Telecom and Kumu Networks have signed a Memorandum of Understanding for technology cooperation on March 2, 2015 at the Mobile World Congress 2015 held in Barcelona, Spain. Kumu Networks, a California-based developer of wireless transmission and signal processing technology, is the leader in the field of IBFD technology.
“SK Telecom is delighted to demonstrate IBFD, a key pre-5G technology, together with Kumu Networks,”said Alex Jinsung Choi, CTO of SK Telecom.“We will continue to drive innovations towards the 5G era by seeking and developing enhanced network technologies with our partners.”
“SK Telecom’s wirelessly controlled traffic robot is the perfect metaphor for Full Duplex’s role in alleviating wireless traffic jams,” said Kumu Networks CEO David Cutrer. “We are very excited to work with SK Telecom as they trial and deploy cutting edge In Band Full Duplex applications to boost today’s wireless network capacity and pave the way to 5G.”
About SK Telecom
SK Telecom (NYSE: SKM, KSE: 017670), established in 1984, is Korea’s largest telecommunications company with more than 28 million mobile subscribers, accounting for around 50% of the market. The company reached KRW 17.164 trillion in revenue in 2014. As the world’s first company to commercialize CDMA, CDMA 2000 1x, CDMA EV-DO and HSDPA networks, SK Telecom launched the nation’s first LTE service in July 2011. SK Telecom also became the world’s first mobile carrier to commercialize 150Mbps LTE-Advanced in June 2013 and 225Mbps LTE-Advanced in June 2014 through Carrier Aggregation(CA). In line with its efforts to swiftly move towards the next-generation mobile network system, or 5G, it successfully commercialized 300Mbps tri-band LTE-A CA. As of the end of March 2015, the company has over 17.4 million LTE and LTE-Advanced subscribers. Based on its strength in network operations business, SK Telecom is seeking new growth engines through three innovative platforms namely Lifestyle Enhancement Platform, Advanced Media Platform and IoT Service Platform. For more information, please visit www.sktelecom.com or email to firstname.lastname@example.org.
Sep 28, 2015
- 5G:haus solves the challenge of sending signals in both directions at the same time over the same wireless channel
- Field trial evaluates In Band Full Duplex (IBFD) capabilities under realistic network conditions for the first time in the world
- IBFD is based on self interference cancellation (SIC) technology from Kumu Networks
5G:haus recently completed a world first field trial of self-interference cancellation (SIC) technology together with Kumu Networks. SIC is a potential 5G technology that allows in-band full duplex communication. In other words, it solves the challenge of simultaneously transmitting and receiving signals at the same time and on the same frequency, thus significantly enhancing the spectral efficiency.
In the field trial which took place on its local network in Prague, Czech Republic, Deutsche Telekom and Kumu Networks were able to evaluate the capabilities of SIC under realistic conditions and test the use of SIC to provide in-band full duplex communication. The field trial focused on measuring the stability and robustness of the technology in a variety of challenging, real-world deployment scenarios. The trial successfully demonstrated the potential of the technology to increase spectral efficiency and its relevance as an enabler for 5G networks.
"I’m delighted to see the first experimental results of a potential 5G technology in DT’s real network environment. We use field trials to get a better understanding of a technology’s potential and that helps us to identify use cases and applications in the context of 5G," says Bruno Jacobfeuerborn, Chief Technology Officer, Deutsche Telekom. "In 5G:haus, we will continue to test and evaluate advanced technologies that pave the way to 5G."
In the 5G:haus framework, Deutsche Telekom is engaging with leading research and industry partners to evaluate potential 5G technology enablers. 5G:haus leverages DT’s European footprint, with trials and evaluations taking place at many different host locations. DT and Kumu Networks cooperation within 5G:haus was announced in March 2015.
"We are pleased to partner with Deutsche Telekom as they take a leading role in exploring next generation wireless technologies on the path to 5G standardization," said Kumu Networks CEO David Cutrer. "DT’s Prague trials provide evidence that the assumed theoretical advantages of self-interference cancelling radios are indeed feasible. We are encouraged to accelerate the commercialization of the technology for near-term applications within the goal of realizing the full potential of the technology in a 5G framework."
In-band full duplex communication has a rich set of potential applications – it is defined in the NGMN Whitepaper as a Technology Building Block for 5G. In the 5G network architecture, it can enable efficient implementation of new radio features to achieve greater spectral efficiency and boost network capacity. Moreover, it can even provide benefits for today’s networks. For example, SIC could solve the small cell backhaul problem by allowing an efficient re-use of spectrum normally exclusively used to serve end-users, thus providing the so-called self-backhauled small cell. This product would allow the network operator to install small cells even in places, where they would otherwise not be possible due to missing or expensive backhaul connectivity.
Deutsche Telekom and Kumu Networks made a world-wide first public demonstration of the self backhauled small cell in June 2015 at the IWPC conference in Bonn.
Deutsche Telekom is one of the world’s leading integrated telecommunications companies with around 151 million mobile customers, 30 million fixed-network lines and more than 17 million broadband lines (as of December 31, 2014). The Group provides fixed network, mobile communications, Internet and IPTV products and services for consumers and ICT solutions for business customers and corporate customers. Deutsche Telekom is present in more than 50 countries and has approximately 228,000 employees worldwide. The Group generated revenues of EUR 62.7 billion in the 2014 financial year – more than 60 percent of it outside Germany.
09/06/15 A step towards an all–band, full-duplex LTE world phone
When it comes to duplexing for devices such as smartphones and tablets, self-interference cancelling technology needs to meet the rigorous low cost requirements of handset applications. Leo Laughlin, PhD student at the University of Bristol’s EPSRC Centre for Doctoral Training (CDT) in Communications and opening speaker at the event, will present a prototype of the full duplex transceiver with electrical balance duplexing that allows transmission and reception from a single antenna. The architecture was designed and built by Laughlin along with MSc student Chunqing Zhang, supervisors Professor Mark Beach and Dr Kevin Morris from the University’s Communication Systems and Networks research group, and CW Radio SIG Champion, Professor John Haine of u-blox AG. The team’s research has been published in this month’s edition of the IEEE Communications Magazine.
During this latest meeting of the CW Radio Special Interest Group, talks will also be heard from Ben Allen, Visiting Fellow, Department of Engineering Science, University of Oxford; Dr Mir Ghoraishi, Project Leader 5G Testbed and Proof-of-Concept, Institute for Communication Systems (ICS), University of Surrey; Samantha Caporal Del Barrio, Industrial Post-Doc, Aalborg University and WiSpry; David Lister, Research Manager at Vodafone UK and Geoff Carey, Director at MIMOtech.
From In-Band Full-Duplex Wireless: Challenges and Opportunities Ashutosh Sabharwal, Philip Schniter, Dongning Guo, Daniel W. Bliss, Sampath Rangarajan, and Risto Wichman
 Femto Forum, “Interference Management in UMTS Femtocells,” February 2010.  M. Duarte and A. Sabharwal, “Full-duplex wireless communications using off-the-shelf radios: Feasibility and first results,” in Proceedings of Asilomar Conference on Signals, Systems and Computers, 2010.  J. I. Choi, M. Jain, K. Srinivasan, P. Levis, and S. Katti, “Achieving single channel, full duplex wireless communications,” in Proceedings of ACM Mobicom, 2010.  M. A. Khojastepour, K. Sundaresan, S. Rangarajan, X. Zhang, and S. Barghi, “The case for antenna cancellation for scalable full-duplex wireless communications,” in Proceedings of the 10th ACM Workshop on HotNets, 2011.  E. Everett, M. Duarte, C. Dick, and A. Sabharwal, “Empowering full-duplex wireless communication by exploiting directional diversity,” in Proceedings of Asilomar Conference on Signals, Systems and Computers, IEEE, 2011.  E. Everett, A. Sahai, and A. Sabharwal, “Passive self-interference suppression for full-duplex infrastructure nodes.” IEEE Transactions on Wireless Communications, to be published. arXiv preprint arXiv:1302.2185.  R. H. Walden, “Analog-to-digital converter survey and analysis,” IEEE Journal on Selected Areas in Communications, vol. 17, no. 4, pp. 539–550, 1999.  P. Angeletti, G. Gallinaro, L. Hili, and X. Maufroid, “Evolution of analog to digital conversion technology for wideband space applications,” in Proceedings of the 23rd AIAA International Communications Satellite Systems Conference (ICSSC 2005), Rome, Italy, pp. 25–28, 2005.  Analog Devices, “AD9683.” http://www.analog.com.  J. Corcoran and K. Poulton, “Analog-to-digital converters – 20 years of progress in “Agilent” oscilloscopes,” Agilent Measurement Journal, pp. 34–40, 2007.  P. Beasley, A. Stove, B. Reits, and B. As, “Solving the problems of a single antenna frequency modulated CW radar,” in IEEE International Radar Conference, 1990.  M. Cryan, P. Hall, S. Tsang, and J. Sha, “Integrated active antenna with full duplex operation,” IEEE Transactions on Microwave Theory and Techniques, vol. 45, no. 10, pp. 1742–1748, 1997.  S. Chen, M. A. Beach, and J. P. McGeehan, “Division-free duplex for wireless applications,” in IEEE Electronics Letters, vol. 34, 1998.  C. Anderson, S. Krishnamoorthy, C. Ranson, T. Lemon, W. Newhall, T. Kummetz, and J. Reed, “Antenna isolation, wideband multipath propagation measurements, and interference mitigation for on-frequency repeaters,” in Proceedings of IEEE SoutheastCon, pp. 110 – 114, Mar 2004.  J. G. Kim, S. Ko, S. Jeon, J. W. Park, and S. Hong, “Balanced topology to cancel Tx leakage in CW radar,” IEEE Microwave and Wireless Components Letters, vol. 14, Sept. 2004.  W.-K. Kim, M.-Q. Lee, J.-H. Kim, H.-s. Lim, J.-W. Yu, B.-J. Jang, and J.-S. Park, “A passive circulator for RFID application with high isolation using a directional coupler,” in 36th European Microwave Conference, pp. 196–199, IEEE, 2006.  C.-Y. Kim, J.-G. Kim, and S. Hong, “A quadrature radar topology with TX leakage canceller for 24-GHz radar applications,” IEEE Transactions on Microwave Theory and Techniques, vol. 55, no. 7, pp. 1438–1444, 2007.  D. W. Bliss, P. A. Parker, and A. R. Margetts, “Simultaneous transmission and reception for improved wireless network performance,” Conference Proceedings of the IEEE Statistical Signal Processing Workshop, Aug. 2007.  J. Sangiamwong, T. Asai, J. Hagiwara, Y. Okumura, and T. Ohya, “Joint multi-filter design for full-duplex MU-MIMO relaying,” in IEEE Vehicular Technology Conference, VTC Spring 2009, pp. 1–5, 2009.  T. Riihonen, S. Werner, and R. Wichman, “Spatial loop interference suppression in full-duplex mimo relays,” in Proceeding of Asilomar Conference on Signals, Systems and Computers, pp. 1508–1512, November 2009.  P. Larsson and M. Prytz, “MIMO on-frequency repeater with self-interference cancellation and mitigation,” in IEEE 69th Vehicular Technology Conference, VTC Spring 2009, pp. 1–5, 2009.  Y. Hua, “An overview of beamforming and power allocation for mimo relays,” in Proceedings of Military Communications Conference (MILCOM), pp. 375–380, 2010.  T. Riihonen, S. Werner, and R. Wichman, “Residual self-interference in full-duplex MIMO relays after null-space projection and cancellation,” in Proceeding of Asilomar Conference on Signals, Systems and Computers, pp. 653–657, November 2010.  M. Duarte, C. Dick, and A. Sabharwal, “Experiment-driven characterization of full-duplex wireless systems,” IEEE Transactions on Wireless Communications, vol. 11, no. 12, pp. 4296–4307, 2012.  M. Jain, J. I. Choi, T. Kim, D. Bharadia, K. Srinivasan, S. Seth, P. Levis, S. Katti, and P. Sinha, “Practical, real-time, full duplex wireless,” in Proceedings of the ACM Mobicom, Sept. 2011.  A. K. Khandani, “Shaping the future of wireless: Two-way connectivity.” http://www.nortel-institute.uwaterloo.ca/content/Shaping Future of Wireless Two-way Connectivity 18ne2012.pdf, June 2012.  E. Aryafar, M. Khojastepour, K. Sundaresan, S. Rangarajan, and M. Chiang, “MIDU: Enabling MIMO full duplex,” in Proceedings of ACM MobiCom, 2012.  M. Duarte, A. Sabharwal, V. Aggarwal, R. Jana, K. Ramakrishnan, C. Rice, and N. Shankaranarayanan, “Design and characterization of a full-duplex multi-antenna system for WiFi networks,” to appear in IEEE Transactions on Vehicular Communications, (arXiv preprint arXiv:1210.1639), 2013.  A. Sahai, G. Patel, and A. Sabharwal, “Pushing the limits of full-duplex: Design and real-time implementation, http://arxiv.org/abs/1107.0607,” in Rice University Technical Report TREE1104, June 2011.  M. E. Knox, “Single antenna full duplex communications using a common carrier,” in IEEE 13th Annual Wireless and Microwave Technology Conference (WAMICON), pp. 1–6, 2012.  D. Bharadia, E. McMilin, and S. Katti, “Full duplex radios,” in Proceedings of ACM SIGCOMM, 2013. 19  B. Chun, E.-R. Jeong, J. Joung, Y. Oh, and Y. H. Lee, “Pre-nulling for self-interference suppression in full-duplex relays,” in Proceedings: APSIPA ASC 2009: Asia-Pacific Signal and Information Processing Association, 2009 Annual Summit and Conference, pp. 91–97, 2009.  P. Lioliou, M. Viberg, M. Coldrey, and F. Athley, “Self-interference suppression in full-duplex MIMO relays,” in Processings of Asilomar Conference on Signals, Systems and Computers, pp. 658–662, 2010.  B. Chun and Y. H. Lee, “A spatial self-interference nullification method for full duplex amplify-and-forward MIMO relays,” in Wireless Communications and Networking Conference (WCNC), 2010 IEEE, pp. 1 –6, Apr. 2010.  D. Senaratne and C. Tellambura, “Beamforming for space division duplexing,” in Proceedings of IEEE International Conference on Communications (ICC), pp. 1–5, June 2011.  T. Riihonen, S. Werner, and R. Wichman, “Mitigation of loopback self-interference in full-duplex MIMO relays,” IEEE Transactions on Signal Processing, vol. 59, pp. 5983 –5993, Dec. 2011.  T. Snow, C. Fulton, and W. J. Chappell, “Transmit-receive duplexing using digital beamforming system to cancel self-interference,” IEEE Transactions on Microwave Theory and Techniques, vol. 59, no. 12, pp. 3494–3503, 2011.  T. Riihonen, A. Balakrishnan, K. Haneda, S. Wyne, S. Werner, and R. Wichman, “Optimal eigenbeamforming for suppressing selfinterference in full-duplex MIMO relays,” in 45th Annual Conference on Information Sciences and Systems (CISS), pp. 1–6, IEEE, 2011.  E. Everett, “Full-duplex infrastructure nodes: Achieving long range with half-duplex mobiles,” Master’s thesis, Rice University, 2012.  B. Day, A. Margetts, D. Bliss, and P. Schniter, “Full-duplex bidirectional MIMO: Achievable rates under limited dynamic range,” IEEE Transactions on Signal Processing, vol. 60, pp. 3702 –3713, July 2012.  B. Day, A. Margetts, D. Bliss, and P. Schniter, “Full-duplex MIMO relaying: Achievable rates under limited dynamic range,” IEEE Journal on Selected Areas in Communications, vol. 30, pp. 1541 –1553, September 2012.  F. O’Hara and G. Moore, “A high performance CW receiver using feedthru nulling,” Microwave Journal, p. 63, September 1963.  A. G. Stove, “Linear FMCW radar techniques,” IEE Proceedings F (Radar and Signal Processing), vol. 139, no. 5, pp. 343–350, 1992.  H. Suzuki, K. Itoh, Y. Ebine, and M. Sato, “A booster configuration with adaptive reduction of transmitter-receiver antenna coupling for pager systems,” in IEEE Vehicular Technology Conference, Fall 1999, vol. 3, pp. 1516 –1520 vol.3, 1999.  K. Lin, Y. E. Wang, C.-K. Pao, and Y.-C. Shih, “A Ka-Band FMCW radar front-end with adaptive leakage cancellation,” IEEE Transactions on Microwave Theory and Techniques, vol. 54, no. 12, pp. 4041–4048, 2006.  J.-W. Jung, H.-H. Roh, J.-C. Kim, H.-G. Kwak, M. S. Jeong, and J.-S. Park, “TX leakage Cancellation via a micro controller and high TX-to-RX ssolations covering an UHF RFID frequency band of 908 to 914 MHz,” IEEE Microwave and Wireless Components Letters, vol. 18, no. 10, pp. 710–712, 2008.  G. Lasser, R. Langwieser, and A. L. Scholtz, “Broadband suppression properties of active leaking carrier cancellers,” in IEEE International Conference on RFID, pp. 208–212, IEEE, 2009.  P. Pursula, M. Kiviranta, and H. Seppa, “UHF RFID reader with reflected power canceller,” IEEE Microwave and Wireless Components Letters, vol. 19, no. 1, pp. 48–50, 2009.  H. Hamazumi, K. Imamura, N. Iai, K. Shibuya, and M. Sasaki, “A study of a loop interference canceller for the relay stations in an SFN for digital terrestrial broadcasting,” in IEEE Global Telecommunications Conference, vol. 1, pp. 167–171, 2000.  K. Lin, R. Messerian, and Y. Wang, “A digital leakage cancellation scheme for monostatic FMCW radar,” in Microwave Symposium Digest, 2004 IEEE MTT-S International, vol. 2, pp. 747–750 Vol.2, 2004.  J. Ma, G. Li, J. Zhang, T. Kuze, and H. Iura, “A new coupling channel estimator for cross-talk cancellation at wireless relay stations,” in IEEE Global Telecommunications Conference, pp. 1–6, 2009.  E. A. Rodriguez, R. L. Valcarce, T. Riihonen, S. Werner, and R. Wichman, “Adaptive self-interference cancellation in wideband fullduplex decode-and-forward MIMO relays,” IEEE Workshop on Signal Processing Advances in Wireless Communications (SPAWC), June 2013.  E. A. Rodriguez, R. L. Valcarce, T. Riihonen, S. Werner, and R. Wichman, “Autocorrelation-based adaptation rule for feedback equalization in wideband full-duplex amplify-and- forward MIMO relays,” IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), May 2013.  T. Riihonen, S. Werner, R. Wichman, and E. Zacarias, “On the feasibility of full-duplex relaying in the presence of loop interference,” in Proceedings of IEEE workshop on Signal Processing and Advances in Wireless Communications, 2009.  H. Ju, E. Oh, and D. Hong, “Catching resource-devouring worms in next-generation wireless relay systems: Two-way relay and full-duplex relay,” IEEE Communications Magazine, vol. 47, pp. 58 –65, September 2009.  D. Ng, E. Lo, and R. Schober, “Dynamic resource allocation in MIMO-OFDMA systems with full-duplex and hybrid relaying,” IEEE Transactions on Communications, vol. 60, no. 5, pp. 1291–1304, 2012.  T. Riihonen, S. Werner, and R. Wichman, “Hybrid full-duplex/half-duplex relaying with transmit power adaptation,” IEEE Transactions on Wireless Communications, vol. 10, pp. 3074 –3085, September 2011.  A. K. Khandani, “Methods for spatial multiplexing of wireless two-way channels,” Oct. 2010. US Patent 7,817,641.  D. Guo and L. Zhang, “Virtual full-duplex wireless communications via rapid on-off-division duplex,” in Proc. of Allerton Conference on Communications, Control and Computing, 2010.  L. Zhang, J. Luo, and D. Guo, “Neighbour discovery for wireless networks via compressed sensing,” Performance Evaluation, vol. 70, pp. 457–471, 2013.  L. Zhang and D. Guo, “Virtual full-duplex wireless broadcasting via compressed sensing,” to appear in IEEE/ACM Transactions on Networking, 2014.  M. Steer, Microwave and RF engineering: A systems approach. Scitech Publishing Inc., 2010.  S. M. Wentworth, Applied Electromagnetics: Early Transmission Lines Approach. John Wiley and Sons Inc., 2007. 20  P. Beasley and A. Stove, “Pilot–an example of advanced FMCW techniques,” in IEE Colloquium on High Time-Bandwidth Product Waveforms in Radar and Sonar, pp. 10/1–10/5, 1991.  EPCGlobal, “ISO18000-6C: EPC Radio Frequency Identity Protocols, Class-l Generation-2 UHF RFID Protocol for Communications at 860MHz to 960MHz,” 2008.  R. Isberg and W. Lee, “Performance tests of a low power cellular enhancer in a parking garage,” in IEEE 39th Vehicular Technology Conference, pp. 542–546, IEEE, 1989.  W. T. Slingsby and J. P. McGeehan, “A high-gain cell enhancer,” in IEEE 42nd Vehicular Technology Conference, pp. 756–758 vol.2, 1992.  W. Slingsby and J. McGeehan, “Antenna isolation measurements for on-frequency radio repeaters,” in Ninth International Conference on (Conf. Publ. No. 407) Antennas and Propagation, pp. 239 –243 vol.1, Apr 1995.  S. J. Kim, J. Y. Lee, J. C. Lee, J. H. Kim, B. Lee, and N. Y. Kim, “Adaptive feedback interference cancellation system (AF-ICS),” in IEEE MTT-S International Microwave Symposium Digest, vol. 1, pp. 627–630 vol.1, 2003.  T. Riihonen, R. Wichman, and J. Hamalainen, “Co-phasing full-duplex relay link with non-ideal feedback information,” in IEEE International Symposium on Wireless Communication Systems, pp. 263 –267, Oct. 2008.  T. Riihonen, S. Werner, J. Cousseau, and R. Wichman, “Design of co-phasing allpass filters for full-duplex OFDM relays,” in Proceedings of Asilomar Conference on Signals, Systems and Computers, pp. 1030 –1034, Oct. 2008.  H. Ju, E. Oh, and D. Hong, “Improving efficiency resource usage in two-hop full duplex relay systems based on resource sharing and interference cancellation,” IEEE Transactions on Wireless Communications, vol. 8, Aug. 2009.  LTE spec, 3GPP TS 36.216 , “Physical layer for relaying operation (release 10),” June 2011.  O. Somekh, O. Simeone, H. Poor, and S. Shamai, “Cellular systems with full-duplex amplify-and-forward relaying and cooperative base-stations,” in IEEE International Symposium on Information Theory, pp. 16–20, 2007.  V. Cadambe and S. Jafar, “Can feedback, cooperation, relays and full duplex operation increase the degrees of freedom of wireless networks?,” in IEEE International Symposium on Information Theory (ISIT), pp. 1263 –1267, Jul. 2008.  S. Simoens, O. Munoz-Medina, J. Vidal, and A. del Coso, “On the Gaussian MIMO relay channel with full channel state information,” IEEE Transactions on Signal Processing, pp. 3588–3599, Sept. 2009.  S. Sohaib and D. K. C. So, “Asynchronous polarized cooperative mimo communication,” in Proceedings of Vehicular Technology Conference, pp. 1–5, April 2009.  T. Riihonen, K. Haneda, S. Werner, and R. Wichman, “SINR analysis of full-duplex OFDM Repeaters,” in PIMRC, Sept. 2009.  K. Yamamoto, K. Haneda, H. Murata, and S. Yoshida, “Optimal Transmission Scheduling for a hybrid of full- and half-duplex Relaying,” IEEE Communications Letters, vol. 15, no. 3, pp. 305–307, 2011.  Y. K. Song and D. Kim, “Convergence of distributed power control with full-duplex amplify-and-forward relays,” in International Conference on Wireless Communications Signal Processing, pp. 1–5, 2009.  Y. Y. Kang and J. H. Cho, “Capacity of MIMO wireless channel with full-duplex amplify-and-forward relay,” in IEEE 20th International Symposium on Personal, Indoor and Mobile Radio Communications, pp. 117–121, 2009.  T. Baranwal, D. Michalopoulos, and R. Schober, “Outage analysis of multihop full duplex relaying,” IEEE Communications Letters, vol. 17, no. 1, pp. 63–66, 2013.  D. W. Bliss and S. Govindasamy, Adaptive Wireless Communications: MIMO Channels and Networks. Cambridge University Press, 2013.  B. Radunovic, D. Gunawardena, P. Key, A. P. N. Singh, V. Balan, and G. Dejean, “Rethinking indoor wireless: Low power, low frequency, full duplex,” tech. rep., Microsoft Research, 2009.  M. Duarte, Full-duplex Wireless: Design, Implementation and Characterization. PhD thesis, Rice University, April 2012.  L. W. Fullerton, “Full duplex ultrawide-band communication system and method,” 1997. US Patent 5,687,169.  S. N. Stitzer, “Full duplex communication system apparatus using frequency selective limiters,” 1982. US Patent 4,325,140.  A. Sahai, G. Patel, C. Dick, and A. Sabharwal, “Understanding the impact of phase noise on active cancellation in wireless full-duplex,” in Proceedings of Asilomar Conference on Signals, Systems and Computers, 2012.  A. Sahai, G. Patel, C. Dick, and A. Sabharwal, “On the impact of phase noise on active cancellation in wireless full-duplex,” arXiv preprint arXiv:1212.5462, 2012.  D. W. Bliss, T. M. Hancock, and P. Schniter, “Hardware phenomenological effects on cochannel full-duplex MIMO relay performance,” IEEE Asilomar Conference on Signals, Systems and Computers, 2012.  E. Ahmed, A. Eltawil, and A. Sabharwal, “Rate gain region and design tradeoffs for full-duplex wireless communications,” submitted to IEEE Transactions on Wireless Communications, 2013.  V. Syrjala, M. Valkama, L. Anttila, T. Riihonen, and D. Korpi, “Analysis of Oscillator Phase-Noise Effects on Self-Interference Cancellation in Full-Duplex OFDM Radio Transceivers,” arXiv preprint arXiv:1401.3521, 2014.  D. Korpi, T. Riihonen, V. Syrjal¨ a, L. Anttila, M. Valkama, and R. Wichman, “Full-duplex transceiver system calculations: Analysis ¨ of ADC and linearity challenges,” arXiv preprint arXiv:1401.3538, 2014.  D. Korpi, S. Venkatasubramanian, T. Riihonen, L. Anttila, S. Otewa, C. Icheln, K. Haneda, S. Tretyakov, M. Valkama, and R. Wichman, “Advanced Self-Interference Cancellation and Multi-Antenna Solutions for Full-Duplex Radios,” in Proceedings of Asilomar Conference on Signals, Systems and Computers, 2013.  L. Anttila, D. Korpi, and V. Syrjal¨ a, “Cancellation of Power Amplifier Induced Nonlinear Self-Interference in Full-Duplex ¨ Transceivers,” in Proceedings of Forty Seventh Asilomar Conference on Signals, Systems and Computers, 2013.  Y.-S. Choi and H. Shirani-Mehr, “Simultaneous transmission and reception: Algorithm, design and system level performance,” Wireless Communications, IEEE Transactions on, vol. 12, pp. 5992–6010, December 2013.  H. Holma and A. Toskala, eds., WCDMA for UMTS: Radio Access for Third Generation Mobile Communications. Wiley, 3rd ed., 2004. 21  A. Kiayani, L. Anttila, and M. Valkama, “Digital Suppression of Power Amplifier Spurious Emissions at Receiver Band in FDD Transceivers,” Signal Processing Letters, IEEE, vol. 21, pp. 69–73, Jan 2014.  M. Omer, R. Rimini, P. Heidmann, and J. Kenney, “A compensation scheme to allow full duplex operation in the presence of highly nonlinear microwave components for 4G systems,” in Microwave Symposium Digest (MTT), 2011 IEEE MTT-S International, pp. 1–4, June 2011.  A. Frotzscher and G. Fettweis, “Digital compensation of transmitter leakage in FDD zero-IF receivers,” Transactions on Emerging Telecommunications Technologies, vol. 23, no. 2, pp. 105–120, 2012.  A. Kiayani, L. Anttila, and M. Valkama, “Modeling and dynamic cancellation of TX-RX leakage in FDD transceivers,” in Circuits and Systems (MWSCAS), 2013 IEEE 56th International Midwest Symposium on, pp. 1089–1094, Aug 2013.  C. S. Vaze and M. K. Varanasi, “The degrees of freedom of MIMO networks with full-duplex receiver cooperation but no CSIT,” arXiv preprint arXiv:1209.1291, 2012.  Q. Geng, S. Kannan, and P. Viswanath, “Interactive interference alignment,” arXiv preprint arXiv:1211.0985, 2012.  A. Sahai, S. Diggavi, and A. Sabharwal, “On degrees of freedom of full-duplex uplink/downlink channel,” in ITW, Sept. 2013.  J. Bai and A. Sabharwal, “Decode-and-cancel for interference cancellation in a three-node full-duplex network,” in Proceedings of Asilomar Conference on Signals, Systems and Computers, 2012.  J. Bai and A. Sabharwal, “Distributed full-duplex via wireless side-channels: Bounds and protocols,” IEEE Transactions on Wireless Communications, vol. 12, no. 8, pp. 4162–4173, 2013.  W. Cheng, X. Zhang, and H. Zhang, “Full duplex wireless communications for cognitive radio networks,” arXiv:1105.0034v1, 2011.  W. Schacherbauer, A. Springer, T. Ostertag, C. Ruppel, and R. Weigel, “A flexible multiband frontend for software radios using high IF and active interference cancellation,” in IEEE International Microwave Simpossium, 2001.  A. Raghavan, E. Gebara, E. M. Tentzeris, and J. Laskar, “Analysis and design of an interference canceller for collocated radios,” IEEE Transactions on Microwave Theory and Techniques, vol. 53, no. 3498-3508, 2005.  N. Singh, D. Gunawardena, A. Proutiere, B. Radunovic, H. Balan, and P. Key, “Efficient and fair MAC for wireless networks with self-interference cancellation,” in International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt), pp. 94 –101, May 2011.  S. Sen, R. Roy Choudhury, and S. Nelakuditi, “No time to countdown: migrating backoff to the frequency domain,” in Proceedings of ACM Mobicom, (New York, NY, USA), 2011.  P. Weeraddana, M. Codreanu, M. Latva-aho, and A. Ephremides, “On the effect of self-interference cancelation in multihop wireless networks,” EURASIP Journal on Wireless Communications and Networking, vol. 2010, no. 1, p. 513952, 2010.  D. Ramirez and B. Aazhang, “Optimal routing and power allocation for wireless networks with imperfect full-duplex nodes,” IEEE Transactions on Wireless Communications, vol. 12, no. 9, pp. 4692–4704, 2013.  X. Fang, D. Yang, and G. Xue, “Distributed algorithms for multipath routing in full-duplex wireless networks,” in Proceedings of the 2011 IEEE Eighth International Conference on Mobile Ad-Hoc and Sensor Systems, MASS ’11, (Washington, DC, USA), pp. 102–111, IEEE Computer Society, 2011.  W. Mesbah and T. Davidson, “Optimal power allocation for full-duplex cooperative multiple access,” in IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), vol. 4, pp. IV–IV, 2006.  M. Gan, D. Guo, and X. Dai, “Distributed ranging and localization for wireless networks via compressed sensing,” arXiv preprint arXiv:1308.3548, 2013.  D. N. C. Tse and P. Viswanath, Fundamentals of Wireless Communication. Cambridge University Press, 2005.  E. Magistretti, K. K. Chintalapudi, B. Radunovic, and R. Ramjee, “WiFi-Nano: Reclaiming WiFi efficiency through 800 ns slots,” in Proceeding of the ACM Mobicom, 2011.  P. Pursula and H. Seppa, “Hybrid transformer-based adaptive RF front end for uhf rfid mobile phone readers,” in IEEE International Conference on RFID, pp. 150–155, 2008.  T. Riihonen and R. Wichman, “Analog and digital self-interference cancellation in full-duplex MIMO-OFDM transceivers with limited resolution in A/D conversion,” in Proceedings of Asilomar Conference on Signals, Systems and Computers, pp. 45–49, November 2012.  T. Schenk, RF imperfections in high-rate wireless systems: Impact and Digital Compensation. Springer, 2008.  E. Ahmed, A. M. Eltawil, and A. Sabharwal, “Self-interference cancellation with nonlinear distortion suppression for full-duplex systems.,” CoRR, vol. abs/1307.3796, 2013.  E. Antonio-Rodriguez, R. Lopez-Valcarce, T. Riihonen, S. Werner, and R. Wichman, “SINR optimization in wideband full-duplex MIMO relays under limited dynamic range,” in Submitted to IEEE Sensor Array and Multichannel Signal Processing Workshop, June 2014.  T. Riihonen, P. Mathecken, and R. Wichman, “Effect of oscillator phase noise and processing delay in full-duplex OFDM repeaters,” in Proceedings of Asilomar Conference on Signals, Systems and Computers, pp. 1947–1951, November 2012.  E. Everett, D. Dash, C. Dick, and A. Sabharwal, “Self-interference cancellation in multi-hop full-duplex networks via structured signaling,” in Proceedings of Allerton Conference on Communication, Control, and Computing, Nov. 2011.  V. Aggarwal, M. Duarte, A. Sabharwal, and N. K. Shankaranarayanan, “Full- or half-duplex? a capacity analysis with bounded radio resources,” in Proceedings of Information Theory Workshop, 2012.  S. Barghi, A. Khojastepour, K. Sundaresan, and S. Rangarajan, “Characterizing the throughput gain of single cell MIMO wireless systems with full duplex radios,” in Proceedings of International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt), May 2012.  F. Baccelli and B. B?aszczyszyn, Stochastic Geometry and Wireless Networks: Volume I Theory and Volume II Applications, vol. 4 of Foundations and Trends in Networking. NoW Publishers, 2009.  M. Haenggi, Stochastic Geometry for Wireless Networks. Cambridge University Press, 2012. 22  C. Fragouli, J.-Y. L. Boudec, and J. Widmer, “Network Coding: An Instant Primer,” ACM SIGCOMM Computer Communication Review, vol. 36, pp. 63–68, Jan. 2006.  S. Zhang, S. chang Liew, and P. P. Lam, “Physical-layer network coding,” in Proc. ACM Mobicom, 2006.  S. Katti, H. Rahul, W. Hu, D. Katabi, M. Medard, and J. Crowcroft, “XORs in the air: Practical wireless network coding,” IEEE/ACM Trans. Networking, vol. 16, pp. 497–510, June 2008.  A. Sahai, G. Patel, and A. Sabharwal, “Pushing the limits of full-duplex: Design and real-time implementation, http://arxiv.org/abs/1107.0607,” in Rice University Technical Report TREE1104, June 2011.  M. Jain, J. I. Choi, T. Kim, D. Bharadia, K. Srinivasan, S. Seth, P. Levis, S. Katti, and P. Sinha, “Practical, real-time, full duplex wireless,” in Proceeding of the ACM Mobicom, Sept. 2011.  Y. Polyanskiy, H. V. Poor, and S. Verdu, “Channel coding rate in the finite blocklength regime,” ´ IEEE Trans. Inform. Theory, vol. 56, pp. 2307–2359, May 2010.  T.-Y. Chen, A. R. Williamson, and R. D. Wesel, “Variable-length coding with feedback: finite-length codewords and periodic decoding,” in Proc. IEEE Int. Symp. Inform. Theory, 2013.  S. Verdu, ´ Multiuser Detection. Cambridge University Press, 1998.  M. L. Honig, Advances in Multiuser Detection. Wiley, 2009.  S. H. Han and J. H. Lee, “An overview of peak-to-average power ratio reduction techniques for multicarrier transmission,” IEEE Wireless Commun., vol. 12, pp. 56–65, 2005.  3GPP TSG RAN WG1 #37, “Comparison of PAR and cubic metric for power de-rating,” Tech. Rep. R1-040642, Motorola, May 2004.  R. N. Braithwaite, “The effects of amplifier nonlinearities and CFR on 64QAM HSDPA waveforms,” in Proc. Microwave Measurement Conf. (ARFTG), pp. 1–3, 2013.
New Technology May Double Radio Frequency Data Capacity
A team of Columbia Engineering researchers has invented a technology—full-duplex radio integrated circuits (ICs)—that can be implemented in nanoscale CMOS to enable simultaneous transmission and reception at the same frequency in a wireless radio. Up to now, this has been thought to be impossible: transmitters and receivers either work at different times or at the same time but at different frequencies. The Columbia team, led by Electrical Engineering Associate Professor Harish Krishnaswamy, is the first to demonstrate an IC that can accomplish this. The researchers presented their work at the International Solid-State Circuits Conference (ISSCC) in San Francisco on February 25.
“This is a game-changer,” says Krishnaswamy, director of the Columbia high-Speed and Mm-wave IC (CoSMIC) Lab. “By leveraging our new technology, networks can effectively double the frequency spectrum resources available for devices like smartphones and tablets.”
In the era of Big Data, the current frequency spectrum crisis is one of the biggest challenges researchers are grappling with and it is clear that today's wireless networks will not be able to support tomorrow's data deluge. Today's standards, such as 4G/LTE, already support 40 different frequency bands, and there is no space left at radio frequencies for future expansion. At the same time, the grand challenge of the next-generation 5G network is to increase the data capacity by 1,000 times.
So the ability to have a transmitter and receiver re-use the same frequency has the potential to immediately double the data capacity of today's networks. Krishnaswamy notes that other research groups and startup companies have demonstrated the theoretical feasibility of simultaneous transmission and reception at the same frequency, but no one has yet been able to build tiny nanoscale ICs with this capability.
“Our work is the first to demonstrate an IC that can receive and transmit simultaneously,” he says. “Doing this in an IC is critical if we are to have widespread impact and bring this functionality to handheld devices such as cellular handsets, mobile devices such as tablets for WiFi, and in cellular and WiFi base stations to support full duplex communications.”
The biggest challenge the team faced with full duplex was canceling the transmitter's echo. Imagine that you are trying to listen to someone whisper from far away while at the same time someone else is yelling while standing next to you. If you can cancel the echo of the person yelling, you can hear the other person whispering.
“If everyone could do this, everyone could talk and listen at the same time, and conversations would take half the amount of time and resources as they take right now,” explains Jin Zhou, Krishnaswamy’s PhD student and the paper’s lead author. “Transmitter echo or ‘self-interference’ cancellation has been a fundamental challenge, especially when performed in a tiny nanoscale IC, and we have found a way to solve that challenge.”
Krishnaswamy and Zhou plan next to test a number of full-duplex nodes to understand what the gains are at the network level. “We are working closely with Electrical Engineering Associate Professor Gil Zussman and his PhD student Jelena Marasevic, who are network theory experts here at Columbia Engineering,” Krishnaswamy adds. “It will be very exciting if we are indeed able to deliver the promised performance gains.”
This work was funded by the DARPA RF-FPGA program.
—by Holly Evarts
By the second half of 2016 we could ship full-duplex solutions for infrastructure applications where the requirements are a bit more relaxed than in a mobile phone.