Making advancements in interference-free spectrum coexistence

The future of wireless communication will be a dynamic interplay of tech innovation, regulatory adaptation, security vigilance, and environmental considerations. 

Advanced wireless systems have revolutionised how people communicate with each other to the point where a majority of the earth’s population now uses cellular mobile phones with other wireless devices. The realm of wireless communications is getting increasingly complex and congested, presenting significant challenges in terms of spectrum coexistence and interference.

"Innovation in spectrum-sharing techniques will be key to addressing spectrum scarcity, with cognitive radio and dynamic spectrum access likely playing significant roles."

Electromagnetic Compatibility (EMC) is crucial for devices to function effectively in their electromagnetic environment without negatively impacting other devices. This requires strong immunity to external signal interference and controlled electromagnetic emissions, often achieved through careful circuit design, filters and shielding. Challenges in EMC arise due to trends towards lower voltage, energy-efficient and compact designs, and cost-cutting measures, which can reduce resistance to Electromagnetic Interference (EMI). Adding radio transceivers and antennas to devices increases the risk of both internal and external interference.

The proliferation of wireless communication systems across a wider electromagnetic spectrum makes maintaining EMC more challenging, leading to coexistence issues. This is especially pertinent in areas with a high concentration of sensitive devices, such as healthcare facilities or using unlicensed or shared spectrum. In India, EMC of devices is not just a technical requirement, but a necessity for ensuring the seamless operation of a vast array of wireless communication systems across an ever-expanding spectrum. Ensuring EMC and coexistence is crucial for the reliability and performance of electronic systems, particularly in critical infrastructure sectors like defence, transportation, communication, healthcare, public safety and Smart Grid systems.

Adhering to EMC and coexistence standards, which realistically reflect the expected electromagnetic environments and usage scenarios, is vital for reliable operation. In radio frequency (RF) communication, interference from unwanted RF signals, either in-band or near-band, is a traditional concern. This is particularly relevant in licensed frequency bands, where all non-licensed signals are considered interference and in shared spectrums, where interference definitions are more complex.

The proliferation of wireless communication systems across a wider electromagnetic spectrum makes maintaining Electromagnetic Compatibility more challenging.

In the case of Smart Grid systems, both interference and coexistence are significant concerns. Interference can be from intended or unintended RF emissions disrupting communications in Smart Grid wireless devices. This interference can vary in time and bandwidth, with different devices responding differently to various waveforms, such as amplitude-modulated or wideband direct sequence spread spectrum signals.

Advancements in spectrum technologies

The evolution of technologies is playing a pivotal role in revolutionising wireless communication, addressing the growing demand for bandwidth in densely populated areas. Dynamic Shared Spectrum (DSS) dynamically allocates frequency bands in real time, catering to the ever-changing requirements of users. In synergy with DSS, Cognitive Radio (CR) intelligently detects and utilises available communication channels, avoiding interference and significantly enhancing spectrum efficiency. Similarly, the integration of Artificial Intelligence (AI) and Machine Learning (ML) into spectrum management has helped improve network performance.

Dynamic Shared Spectrum: This involves dynamically allocating frequency bands to users based on real-time usage and requirements. This approach is particularly beneficial in densely populated areas where the demand for spectrum is high. DSS operates by transmitting 4G Long Term Evolution (LTE) and 5G New Radio (NR) signals over a shared frequency. This technology dynamically assigns cellular resources between both networks depending on current demand.

Cognitive Radio Technology: It is a form of wireless communication in which a transceiver can intelligently detect which communication channels are in use and which are not. It instantly moves into vacant channels while avoiding occupied ones. It does not cause any interference to the licensed user. Given India’s spectrum scarcity and the high demand for wireless services, CR technology can significantly enhance spectrum efficiency by dynamically identifying and utilising available channels.

Artificial Intelligence and Machine Learning: AI and ML are transforming network management by enhancing performance and managing interference in complex RF environments. They have made immense contributions, ranging from predictive analytics to automated optimisation, fault detections and self-healing, improvements in security and energy usage, and network slicing.

Predictive analytics involves the examination of network data to predict traffic patterns, facilitating optimal resource allocation and preventing congestion.

Predictive analytics, for instance, involves the examination of network data to predict traffic patterns, facilitating optimal resource allocation and preventing congestion. Automated optimisation, driven by AI algorithms, dynamically adjusts network parameters in real time, reducing manual intervention and increasing operational efficiency. The fault detection and self-healing capabilities of AI swiftly identify and rectify network issues, often resolving problems before they impact users, thereby minimising downtime and enhancing reliability.

Furthermore, AI contributes significantly to security enhancements by efficiently detecting and responding to threats, identifying attack patterns, and taking pre-emptive actions to safeguard the network. In terms of energy efficiency, AI plays a crucial role in optimising the energy consumption of network infrastructure, which becomes increasingly vital as networks expand and energy costs rise.

In the context of 5G networks, AI and ML manage network slicing to allocate resources effectively for various services, ensuring each service receives the necessary resources without adversely affecting others. Additionally, AI enhances data processing at the network edge, resulting in reduced latency and improved response times, particularly beneficial for critical applications such as autonomous vehicles and industrial automation.

Changing technologies and techniques

The evolution of wireless communication technologies has been instrumental in meeting the burgeoning demands of modern communication networks. Among these, several key techniques stand out for their impact on enhancing network performance, reducing interference, and optimising resource utilisation.

Beamforming: This signal processing technique, used in antenna arrays, directs transmission power specifically towards receivers, improving signal quality and reducing interference.

MIMO technology: Multiple Input Multiple Output (MIMO) uses multiple antennas at both transmitter and receiver ends, enabling communication with multiple users over the same frequency band, thereby boosting network efficiency and capacity.

RU scheduling in 5G networks: Resource Unit or RU scheduling allocates the smallest units of time and frequency among users, optimising network throughput and ensuring fair resource distribution.

Spatial reuse: This involves reusing frequency bands in different spatial locations or by different users within the same area to maximise throughput while managing interference, especially in dense networks.

Channel bonding: It combines adjacent frequency channels into a single, wider channel, increasing bandwidth and data throughput, often used in Wi-Fi technologies. However, it requires careful management to avoid increased interference in crowded spectrum areas.

With wireless networks increasingly underpinning critical infrastructure and services, safeguarding against cyber threats and ensuring communication integrity are paramount.

Challenges and future directions

As we delve into the future of wireless communications, we face a multifaceted landscape of challenges and opportunities. One of the primary hurdles is managing the increasing scarcity of the spectrum in the face of burgeoning device numbers and data demands. Efficiently allocating and utilising this limited resource is crucial. Concurrently, interference management remains a persistent technical challenge, especially in densely populated areas where multiple wireless technologies coexist. The growing complexity of networks, particularly with the advent of 5G and the anticipated arrival of 6G, adds another layer of complexity, necessitating seamless integration and compatibility among diverse devices and technologies.

On the regulatory front, the evolving spectrum of regulations and the need for international coordination present their own set of challenges. Aligning global spectrum management strategies is essential but often complicated by differing national interests and regulatory frameworks.

Additionally, security concerns are more prominent than ever. With wireless networks increasingly underpinning critical infrastructure and services, safeguarding against cyber threats and ensuring communication integrity are paramount.

Looking ahead, the emergence of 6G promises even faster speeds and more reliable connections, potentially exploring new spectrum bands and incorporating cutting-edge technologies like AI and quantum communication. Innovation in spectrum-sharing techniques will be key to addressing spectrum scarcity, with cognitive radio and dynamic spectrum access likely playing significant roles. The integration of AI and ML will further advance, streamlining network management and optimisation. Moreover, there’s a growing emphasis on developing sustainable and energy-efficient communication technologies, aligning with global environmental consciousness and the need for greener network infrastructures.

The future of wireless communication is set to be a dynamic interplay of technological innovation, regulatory adaptation, security vigilance, and environmental consideration. Navigating these challenges and opportunities will require continuous innovation, strategic planning, and international collaboration.

The author is a decorated military veteran who retired as the Signal Officer in Chief - the head of the ICT wing of the Indian Army. He was also the first CEO of the Telecom Sector Skill Council (TSSC) and is presently the Director General of the Cellular Operators Association of India (COAI).

Lt Gen Dr S P Kochhar

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