OFDM

Executive Summary:

Cohere Technologies has won a $28 million U.S. government contract funded by the FutureG Office within the U.S. Department of War (previously called the Defense Department or DoD) to develop a multi-waveform RAN prototype for integrated sensing and communications (ISAC), with Cohere’s Zak-OTFS as a core waveform alongside conventional OFDM [1]. The DoD award expands on a National Science Foundation VINES Phase 2 project. It will fund the development of a sovereign, mission-first ISAC capability that leverages existing and future commercial 5G/6G infrastructure to provide persistent aerial and ground surveillance while remaining indistinguishable from ordinary cellular traffic.

Mission: The contract is intended to turn commercial cellular infrastructure into a sensing layer for detection, tracking, and response applications, especially drone defense. Cohere says the prototype will support a multi-waveform software stack, a mobile test platform, and a layered inference sensing system that converts delay-Doppler data into real-time 3D tracks with classification and confidence scoring.

Cohere is positioning OTFS [2.] via its Pulsone/Zak-OTFS technology, as the waveform that better fits high-Doppler sensing and communications than plain OFDM. The company argues that OTFS carries information in the delay-Doppler domain, which is useful when the same signal must communicate and sense moving targets such as drones. If successful, this DoD funded ISAC demo could give OTFS a stronger credibility boost with standards bodies, equipment vendors, and defense customers, even if it does not immediately make OTFS a mainstream 3GPP waveform.

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Definitions and Comparison: OFDM vs. OTFS:

Note 1. OFDM (orthogonal frequency division multiplexing) is the 1D time-frequency workhorse that dominates WiFi, 4G and 5G because it is simpler, mature, and standardized by IEEE 802.11, ITU-R, and ETSI. OFDM maps data onto orthogonal subcarriers in the frequency domain, with symbols arranged over time and frequency; it is the basis of 4G LTE and is also used in 5G NR. OTFS maps data in the delay-Doppler domain and then spreads each symbol across the time-frequency plane, so the receiver sees a more invariant coupling to the channel under high Doppler and multipath.

Note 2. OTFS (orthogonal time frequency space) modulation is best thought of as a 2D, delay-Doppler-native waveform that Cohere has championed for highly mobile and doubly selective channels. It’s main advantage over OFDM is that it can make the channel look more stable to each symbol in fast-varying, high-Doppler environments, whereas OFDM excels when channels are relatively well-behaved and implementation efficiency matters most.

Aspect	OTFS	OFDM
Best channel condition	High mobility, high Doppler, strong time variation	Quasi-stationary or modestly varying channels
Channel view	Delay-Doppler domain, more invariant symbol coupling	Time-frequency domain, channel varies per subcarrier/time slot
Equalization burden	Potentially easier in challenging channels, especially with mobility	Well understood and efficient in mainstream deployments
Standardization	Emerging, not yet the default cellular waveform comsoc+1	Fully embedded in 4G/5G ecosystems
Maturity	Less mature, more research/prototype-driven	Very mature, widely deployed

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Quotes and Capabilities:

“ISAC is a mission-first priority for the U.S. Department of War to defend against drone swarms. Due to guidance from leadership to execute rapidly, we required a partner with the right technology ready today,” said Tom Rondeau, Principal Director for FutureG, OUSW(R&E). “As a proven innovator with a demonstrated ability to build multi-waveform platforms, Cohere Technologies offered a clear path that we could move on immediately. Their OTFS modulation carries information directly in the sensing domain, delivering massive communications and sensing performance advantages in high-Doppler environments. This solution rapidly delivers critical ISAC capabilities while building on our ‘innovate-first’ posture, demonstrating the tremendous opportunity for innovation brought by the FutureG Open Centralized Unit Distributed Unit (OCUDU) platform.”

The multi-waveform system prototype is designed to provide detection, classification, tracking, and defeat-cueing of drone threats while operating in commercial spectrum bands, making it difficult for adversaries to distinguish sensing activity from normal cellular communications. In addition to core defense applications-including battlefield awareness, border security, and critical infrastructure protection-the program will identify parallel commercial use cases such as Advanced Air Mobility, smart city traffic management, and public safety. Work under the contract will be executed in close collaboration with government technical authorities and program partners.

“This ISAC contract from DoW represents a major milestone for Cohere and for the future of dual-use wireless technology,” said Ray Dolan, Chairman and CEO of Cohere Technologies. “By combining our Pulsone Technology with conventional Orthogonal Frequency-Division Multiplexing (OFDM) in a flexible, software-defined architecture, we can deliver high-performance sensing that is affordable, scalable, and operationally invisible-exactly what is needed to counter the growing threat of sophisticated drone and Unmanned Aerial Systems (UAS).”

Key Capabilities to Be Developed Under the Program:

A Multi-Waveform physical layer running on an open, extensible software stack that supports both traditional 4G and 5G OFDM and Pulsone Technology using the Zak-OTFS waveform.
A Mobile Test Platform enabling bi-static and multi-static sensing configurations.
A Layered Inference Sensing system that converts raw Delay-Doppler data into real-time 3D tracks with classification and confidence scoring.
Realistic outdoor test environments supporting mono-static, bi-static, and multi-static sensing.
Compliance with the FutureG OCUDU platform and Zero Trust security requirements.

“This ISAC project award validates Cohere’s long-term vision of building sovereign, future-proof wireless infrastructure that serves both national security and commercial markets,” Dolan added. “We are proud to work alongside the FutureG Office and partners to deliver technology that strengthens our nation’s ability to sense and respond in contested environments.”

Cohere and the FutureG Office are considering commercial applications like Advanced Air Mobility traffic management, smart-city applications, and public safety are all named as potential adjacent markets, continuing the dual-use framing the Pentagon has increasingly favored for next-gen wireless R&D.

Caveats and 6G NR/IMT 2030 RIT Standards Outlook:

The public information so far is largely company-announced, so the contract details, schedule, and technical requirements should be treated as initial disclosures rather than a full program specification. Also, the award appears to fund a prototype and operational demonstration, not a guaranteed path to standards adoption or mass deployment. While it is certainly possible for OTFS to be accepted as an IMT 2030 RIT (Radio Interface Technology), 3GPPs submission (via ATIS) to ITU-R WP5D will almost surely be OFDM based version of 6G NR.

ITU-R WP 5D has published the IMT-2030 roadmap and invited RIT-candidate submissions in the 02/2027 to 02/2029 window, so the process is still open to proposals. WP 5D’s role is to define the overall radio system aspects for IMT, but it does not itself guarantee adoption of any one waveform; candidates must survive technical performance requirements, evaluation criteria, and national/industry consensus. That means OTFS can still be proposed, but it would need to show clear benefits under the evaluation framework and broad support from proponents.

To get adopted, OTFS would need to prove more than attractive simulation results. It would need implementable receiver complexity, backward-compatible deployment pathways, acceptable PAPR and synchronization behavior, and a compelling story for mass-market devices, not just high-mobility or ISAC use cases. The literature and industry commentary generally position OTFS as strongest where Doppler and sensing matter most, which helps its case but may also narrow its scope.

The most realistic 6G/IMT 2030 standards scenario is:

3GPP keeps OFDM-family waveforms as the baseline for 6G NR.
OTFS remains active in research, patents, and trial implementations.
OTFS is considered for targeted IMT-2030 RIT use cases such as high mobility, NTN, or integrated sensing and communications, rather than universal deployment.

Conclusions:

The U.S. government is backing Cohere’s OTFS-centered ISAC concept with real funding, and the strategic aim is to fuse communications and sensing in a way that is harder for drones or other threats to detect. For OTFS, that is a meaningful validation event, but still a prototype-stage win rather than proof of broad cellular standardization.

Cohere’s OTFS is not “better OFDM”; it is a different design point optimized for a harder channel model. OFDM remains the incumbent because it is standardized and efficient, but OTFS has a credible technical case where Doppler and channel variation are the real bottlenecks.

About Cohere Technologies:
Cohere is the innovator of Universal Spectrum Multiplier (USM) software for 4G, 5G, and Multi-G. USM significantly improves mobile networks in any FDD and TDD spectrum band – and Pulsone™ Technology which is based on the Zak-OTFS waveform for ISAC and NTN. Pulsone is a trademark of Cohere Technologies. Cohere is headquartered in San Jose, Calif. (USA). www.cohere-tech.com

About the FutureG Office:
The FutureG Office within the Office of the Under Secretary of War for Research and Engineering is responsible for the strategic assessment and research and development of FutureG technologies to confer long-term economic, military and security advantages to the United States of America and its allies. By strengthening and developing relationships with private industry, academia, interagency and international allies and partners, the FutureG Office promotes the use of common, commercial standards for DoW operations, encourages adoption of open and interoperable technologies, and advances critical next-generation wireless network capabilities.

About the OCUDU Ecosystem Foundation:
The OCUDU Ecosystem Foundation, hosted by the Linux Foundation, is a global public-private initiative dedicated to building a commercial and research ecosystem around a production-ready, open source CU/DU stack. By fostering collaboration across the entire RAN lifecycle, from R&D to end-to-end integration, the OCUDU Ecosystem Foundation provides the reference architectures, conformance tooling, and “super blueprints” required to scale Open RAN from pilot projects to global production.

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References:

COHERE TECHNOLOGIES WINS $28 MILLION U.S. GOVERNMENT CONTRACT TO DEVELOP MULTI-WAVEFORM RADIO ACCESS NETWORK (RAN) FOR INTEGRATED SENSING AND COMMUNICATIONS (ISAC)

https://www.lightreading.com/6g/us-defense-dept-backs-6g-rival-to-tech-used-by-ericsson-and-nokia