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
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
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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.