This Nature Communications article introduces a novel integrated sensing and communication (ISAC) system using a space-time-coding metasurface. The metasurface allows simultaneous beamforming for communication and radar sensing by manipulating electromagnetic waves in both space and time. Specifically, the researchers designed a digital coding pattern applied to the metasurface elements, enabling dynamic control of the generated beam. This technique achieves high data rates for communication while also providing accurate target detection and localization. The proposed ISAC system demonstrates significant performance improvements compared to traditional separated systems, offering a promising path toward more efficient and versatile wireless technologies.
This blog post details the author's successful, yet extremely tight, implementation of a full Wi-Fi networking stack (including TLS) on the memory-constrained nRF9160. Using the Zephyr RTOS, they managed to squeeze in lwIP, mbedTLS, and other necessary components, leaving only about 1KB of RAM free. This required careful configuration and optimization, particularly within lwIP, to minimize memory usage without sacrificing essential functionality. The author highlights the challenges of working with the nRF9160's limited resources and shares specific configuration adjustments, such as reducing TCP window size and disabling IPv6, that enabled them to achieve a working Wi-Fi connection. The post serves as a practical demonstration of pushing the boundaries of what's possible on this resource-constrained platform.
Hacker News users discussed the challenges and ingenuity of fitting a full Wi-Fi stack onto the resource-constrained nRF9161. Several commenters expressed admiration for the author's accomplishment, highlighting the difficulty of working with such limited resources. Some questioned the practical applications, given the nRF9161's integrated cellular modem and the availability of smaller, cheaper Wi-Fi microcontrollers. Others suggested potential uses like captive portals or bridging between cellular and local networks. The Zephyr RTOS was mentioned as a contributing factor to the project's success due to its small footprint. One commenter shared their experience with similar memory constraints on embedded systems and offered debugging advice. The discussion also briefly touched on the implications of this achievement for IoT devices and the potential for further development in low-resource Wi-Fi applications.
The IEEE Spectrum article argues that the current trajectory of 6G development, focused on extremely high frequencies and bandwidth, might be misguided. While these frequencies offer theoretical speed improvements, they suffer from significant limitations like extremely short range and susceptibility to atmospheric interference. The article proposes a shift in focus towards utilizing the existing, and largely underutilized, mid-band spectrum for 6G. This approach, combined with advanced signal processing and network management techniques, could deliver substantial performance gains without the drawbacks of extremely high frequencies, offering a more practical and cost-effective path to a truly impactful next-generation wireless network.
HN commenters largely agree that focusing on 6G is premature and driven by hype, especially given 5G's under-delivered promises and niche applications. Several express skepticism about the need for the speeds 6G promises, arguing current infrastructure improvements and better utilization of existing technologies are more pressing. Some suggest focusing on improving coverage, affordability, and power efficiency instead of chasing higher theoretical speeds. There's also concern about the research itself, with comments highlighting the impracticality of some proposed technologies and the lack of clear use cases beyond vague "future applications." A few commenters point out the cyclical nature of these G cycles, driven by marketing and telco interests rather than genuine user needs.
Summary of Comments ( 1 )
https://news.ycombinator.com/item?id=43261825
Several Hacker News commenters express skepticism about the practicality of the research due to the complexity and cost of implementing the proposed metasurface technology. Some question the real-world applicability given the precise calibration requirements and potential limitations in dynamic environments. One commenter highlights the inherent trade-off between sensing and communication functionalities, suggesting further investigation is needed to understand the optimal balance. Another points out the potential security implications, as the integrated system could be vulnerable to new types of attacks. A few commenters note the novelty of the approach, acknowledging its potential for future applications if the technological hurdles can be overcome. Overall, the discussion revolves around the feasibility and limitations of the technology, with a cautious but intrigued perspective.
The Hacker News post titled "Integrated sensing and communication based on space-time-coding metasurfaces" (https://news.ycombinator.com/item?id=43261825) has a modest number of comments, sparking a discussion primarily around the practical applications and limitations of the research presented in the linked Nature article.
One commenter expresses skepticism about the real-world applicability of the technology, questioning the feasibility and cost-effectiveness of deploying such complex systems. They highlight the challenges associated with manufacturing and scaling the "metasurfaces" described in the research, suggesting that the current state of the technology is far from practical deployment. This comment raises a crucial point about the gap between theoretical research and its translation into tangible, commercially viable products.
Another commenter focuses on the specific application of this technology in autonomous vehicles, pointing out the limitations of relying solely on reflected signals for sensing. They argue that relying on reflections could lead to inaccurate or incomplete environmental perception, potentially causing safety issues. This comment introduces a valuable consideration for the specific use case of autonomous driving, highlighting the need for robust and reliable sensing mechanisms.
A further comment delves into the potential security implications of using this technology, specifically mentioning the possibility of jamming or spoofing the signals. This raises a critical concern about the vulnerability of such systems to malicious interference, emphasizing the importance of addressing security considerations in the development and deployment of this technology.
One commenter draws a parallel between the described technology and phased array radar, suggesting that the core principles are not entirely novel. They acknowledge the potential advantages of the proposed approach but also imply that the technology represents an evolution rather than a revolutionary breakthrough. This comment provides context and helps ground the discussion by relating the research to existing technologies.
Finally, another comment briefly touches upon the potential of the technology in medical imaging applications, though without going into much detail. This comment suggests a broader scope of application beyond autonomous driving and communication, hinting at the possible versatility of the technology.
While the comments are not extensive, they represent a range of perspectives on the potential impact and challenges associated with the research, covering aspects of practicality, safety, security, novelty, and potential applications. They effectively highlight both the excitement and the realistic limitations of this emerging technology.