By Tomasz Waliwander, Chief Executive Officer at Farran Technology Introduction Lately, there has been a lot of buzz about how 5G – the new generation communications technology – is going to improve our lives and boost economic growth which is much needed in the post covid world. 5G is to enable connectivity services with abundant availability, very high reliability and low latency. In comparison with 4G, with up to 100x higher data rates and 10x lower latency (the delay between sending and receiving information), it is expected to enable 1,000x higher data volumes and 100x more devices to be simultaneously connected to a network. 5G is touted to make our society more connected and free to stream high-definition video content or engage in AR/VR enhanced real-time online gaming experiences anywhere. This new generation communications technology is proclaimed as a key enabler of new use cases such as smart manufacturing, smart agriculture, smart energy, autonomous driving and logistics to name just a few. While 5G is early in its lifecycle and is being continuously enhanced and refined with new 3GPP releases, it is important to address and understand what role the mm-wave spectrum will have in enabling 5G to deliver on its promises. This post will describe briefly what millimeter waves are and discuss the importance of the mm-wave spectrum in enhancing broadband services. As its characteristics are still not well understood, we will also present the benefits as well as discuss the challenges associated with transmitting radio waves at very high frequencies.        What is the millimeter wave spectrum? Millimeter waves are a subset of an electromagnetic spectrum that spans from 30 GHz to 300 GHz [1]. Due to its properties (discussed in subsequent section) it is a frequency band that is increasingly researched, studied and adopted for high-speed wireless communication. As mobile data transfer levels have surpassed those of the wired communication and are projected to increase each year for the foreseeable future, the need for enhanced data performance of networks and bandwidth shortages of sub-7GHz spectrum, make the mm-wave spectrum a very attractive proposition. With the benefits of mm-waves also come the challenges and issues that need to be addressed by researchers and engineers, who are tasked with development and deployment of 5G devices, systems and networks. 5G systems are being implemented to operate below 1 GHz, Sub-7GHz (1-7.1GHz) and mm-wave range, with the most recently finalized by 3GPP Release 16 defining the later as a spectrum between 24.25 and 52.6 GHz. The work continues on Release 17, which will introduce further feature enhancements and is expected to support the spectrum up to 71 GHz [2]. What makes millimeter waves critical in the 5G future success? The millimeter wave spectrum offers several benefits and opens new opportunities for 5G, which were left untapped by all previous communication technologies. Here are five attributes that the mm-waves enable which are fundamental to 5G realizing it’s potential. Larger bandwidths The wireless spectrum is a heavily occupied resource, especially in the low- and mid-band range (up to 7GHz). The high-band (24.25-52.6 GHz) – the 5G mm-wave spectrum – is by contrast a much broader band in absolute terms than the sub-7GHz band. It is also much less crowded and not as heavily used, making a tremendous amounts of bandwidth capacity available for new applications and use cases such as: enhanced mobile broadband (eMBB) enabling broadband everywhere, smart offices, connected vehicles, and enhanced multimedia. massive internet of things for smart buildings and cities, agriculture and environment, transport & logistics, and consumer wearables. ultra-reliable low latency applications for: mission critical machine type communication, process & factory automation, public safety and disaster recovery, healthcare and remote surgery. Small antenna form factor As the radio signal wavelength is inversely proportional to frequency, the mm-wave spectrum allows for deployment of antenna arrays that, although compact in size, are capable of delivering very high far field gains and help overcoming increased propagation losses (further discussed below). For example, an antenna array at 70 GHz would be a ¼ of the size of an antenna designed for 30 GHz. Low latency Latency is the time taken for a signal to travel from the source to destination and returns back to the source [4]. One of the promises of 5G is that it is expected to provide latency in an order of milliseconds, ideally achieving even less than 1 mS. This is to be achieved by both a more efficient data transmission protocol as well as by using high frequency millimeter wave signals – the higher the frequency, the lower the theoretical limit of latency. The question remains however: Why do we need low latency? There are several use cases and real-time applications for which latency, more so than a higher data rates, is much more important. One example are autonomous vehicles that will be moving at high speeds and require real-time information about their surroundings. Another application is factory automation, that with low latency wireless connectivity for all machine types, communication will allow to increase the utility and efficiency of robots [4].   Low latency is fundamental to providing healthcare access to all, even the most remote patients and performing remote surgeries to extend the reach of expert medical personnel and help address staff shortages in the future. In these cases, haptic and video feedback as well as robotic response must be minimized and put a stringent demand on the network with latency demand of lower than 20 mS [5]. Other use cases that require a quick, low latency real-time communications are emergency response, disaster recovery and public safety [3]. Lastly, user experience of online gaming is largely dependent on low latency more so than the sheer download and upload speeds. High network densification Due to significantly higher propagation losses, the transmission range of mm-waves is considerably reduced in comparison with sub-7 GHz networks [3]. Providing the required coverage requires a larger number of cells to be deployed as a part of 5G mm-wave networks. This network densification