mmWave 5G: Past, Present and Future

Journey of mmWave 5G:  from the lab to the world

The story of mmWave 5G started in a small lab about a decade ago. Its journey from a research concept to a dominant 5G technology with global adoption is a testament of the amazing power that stems from the very human spirit of continuous exploration and challenging the status quo.

Around a decade ago, the prevailing view in the research community was that the mmWave spectrum is suitable only for short-range communications, largely due to the higher propagation loss and the lack of high efficiency RF components in these frequency bands. In 2009, researchers at Samsung discovered the application of cutting-edge beamforming technology could effectively overcome the technical challenges in the mmWave band [2]. The researchers went on and proposed to use the mmWave bands for future generation wireless communications in a 2011 IEEE magazine paper [3].

To accelerate the development of this emerging 5G technology, in 2012 Samsung established a “Next Generation Communications Lab” to lead the mmWave evolution. The next few years are filled with excitement, as the researchers achieved one breakthrough after another to help usher in the new era of mmWave communication. The world’s first 5G communications using 28 GHz spectrum made headlines in 2013 with speed of 1 Gbps [4]. It was followed by a race-track mobility test in 2014, where Samsung showcased the high-speed beam tracking capability that achieved a stable 1.2 Gbps throughput at 110 km/h. In-depth analysis of beam-forming technology was summarized in a 2014 IEEE magazine paper [5].

As the saying goes “Rome is not built in a day”, taking a new technology from lab to the real-world requires patience and perseverance. Many engineering challenges emerged along the way, including multi-cell handover, digital-analog hybrid beamforming, and high efficiency mmWave Radio Frequency Integrated Circuit (RFIC). Samsung engineers worked tirelessly to solve these real-world problems and the collective efforts eventually culminated in the 5G pre-commercial services debut during the winter sports games in February 2018, and the first fixed wireless access (FWA) service using mmWave 5G technology started in the U.S. [6]. More recently in April 2020, Samsung continued to push the boundary and  demonstrated industry’s fastest 5G speeds of 8.5 Gbps speed across two devices using 800 MHz of spectrum and MU-MIMO technology in a lab (approximately 4.3 Gbps speed on each device) [1]. Samsung is also currently working on expanding the coverage of mmWave FWA services to a few kilometers.

Samsung’s relentless efforts in the mmWave technology has led to the commercial rollout of various mmWave 5G end-to-end solutions. In 2019, Samsung introduced Compact Macro, one of the simplest radio network configurations in the industry that integrates the baseband, radio and antenna all together in a small form factor. It uses advanced in-house modems, radio frequency integrated circuits (RFICs) and digital analog front end (DAFE) ASICs to support all mmWave frequency bands with high performance and low power consumption [7]. To extend 5G mmWave services to indoor environments, Samsung has also introduced 5G mmWave small cells (Link Cell) in September 2020 [8]. Both Compact Macro and Link Cell solutions are currently driving 5G mmWave commercialization efforts in the North American market.

Global Collaboration and Standardization: It Takes a Village

Cellular wireless technology is extremely complex, and successful commercialization of mmWave 5G technology in the past decade was in large part thanks to the close collaboration among many stakeholders in the ecosystem, including national government regulatory bodies and research organizations, standard bodies, academic researchers, global operators, RF/RFIC and other components vendors, semiconductor manufacturers, network infrastructure and smart phone vendors.

Samsung has always been a strong advocate and leader for government/industry/university collaboration in an effort to foster an open and robust 5G technology ecosystem.  We contributed to a popular IEEE 5G vision paper [10] to help shape the direction of the 5G technology so that the ecosystem partners can focus their efforts and channel their energy around a few key drivers such as mmWave and FD-MIMO. We also took an active role to address one of the bottlenecks facing the community in the early days of the mmWave technology development and standardization: the lack of a high fidelity channel model for the mmWave spectrum bands. I served as the steering committee chair of the 5G Channel Model Alliance organized by U.S. National Institute of Standards and Technology [11], where we brought together 100+ top experts in the channel model field around the world to share their learnings and to improve the quality of the channel model at the mmWave band. I also led the early effort of standardizing these channel modes in 3GPP as a co-Rapporteur for the 3GPP mmWave channel-model study item [12]. I am very grateful to have had a front-row seat to witness this part of 5G history unfolding, and will always be inspired by the energy, enthusiasm and dedication I have seen from many of the engineers from both research and standard communities.

Despite the early commercial success of 5G mmWave technology, significant practical deployment challenges remains, especially in the areas of coverage improvement, mobility enhancement and efficient standalone deployment. Samsung is committed to bring innovative solutions to close these gaps through global collaboration and standardization. We were one of the three companies jointly proposed the Integrated Access and Backhaul (IAB) idea to 3GPP in 2017 [13], which could be the key to enable extended coverage 5G Compact Macro without costly densification of transport network (fiber point of presence). Recently we are also actively collaborating with other companies in 3GPP to enable the deployment of multiple transmit and receive points (TRP) network operation, as it can significantly improve the user experience at cell edges.

mmWave Technology: Future is Bright

Commercial deployment of mmWave 5G network has continued to pick up its pace. As of October 2020, mmWave 5G service is available in more than 55 cities, 43 stadiums and arenas, and 7 airports in the U.S. [14]. Samsung is committed to providing a broad portfolio of mmWave 5G products to meet the diverse needs of operators in the leading markets including Japan, Korea, the U.S and more.

GSMA Intelligence recently completed their study about the economics of mmWave 5G [15]. They showed that mmWave can be a cost-effective deployment strategy for dense urban networks, indoor enterprises, and fixed wireless access scenarios. With rapidly increasing data traffic demand, the economic payoff of mmWave technology could be achieved by as early as year 2025. The study would certainly encourage the operators around the world to accelerate the mmWave 5G deployment.

On the device side, the number of smartphones equipped with mmWave 5G capability has been growing [16]. More consumers can have the first-hand experience of this amazing technology. We expect that more vertical markets and use cases will emerge to take advantage of this ultra-high speed data pipe for mobile users. The rollout of mmWave 5G will open the door to a bright and exciting future with many new applications that are yet to be dreamt up.