Market Insight

Beyond LTE: Advancing to 5G Wireless Technology

December 23, 2015

Robert Braverman Senior Director, Commercial Product Management

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Not long ago cellular enabled devices were used simply for humans to verbally communicate with one another, with telephone calls being the only viable option. Over the past two decades mobile broadband internet access has helped transform communication from voice only to a plethora of data-based experiences. Video, social networking, multiplayer gaming, and cloud based multimedia and storage services have created an environment in which users can now share experiences with one another.

The aforementioned evolution of communication has occurred alongside the first half decade of commercially available LTE networks, and the technology is progressing further to enhance the mobile broadband experience. As LTE enters its second half-decade of availability it’s important to note that the development and design of the technology actually began to take place over 10 years ago, years before the first iPhone was available. While those setting the standards had incredible vision to anticipate many of the attributes required to facilitate today’s applications, a new 5G technology framework will be required to improve the mobile broadband user experience. Just as the progression from 3G to 4G did with use cases such as video calling, 5G will make useable those applications that are just now becoming possible but not yet ready for primetime. Applications that are in nascent stages of development today, such as autonomous vehicles, may become commercially viable with 5G; and the technology will help to accelerate the development of the internet of things (IoT). Further, applications and use cases which are currently outside of the realm of what is thought possible will also become reality.

Better Mobile Broadband

LTE Advanced (LTE-A) and LTE Advanced Pro (LTE-A Pro) are two successive evolutions of the existing LTE standard to address throughput, efficiency, and capacity challenges presented by the current set of mobile broadband applications and use cases. LTE-A enabled devices and networks are already active and continuing to roll out across the globe and LTE Advanced Pro will be introduced in the 3GPPs releases 13 and 14.

While many LTE-A networks around the world are now able to combine separate blocks of spectrum to increase throughput and spectral efficiency, few operators can leverage three 20 MHz-wide channels required for the full effectiveness of carrier aggregation.  In order to accommodate the growing demand for faster mobile connections, 5G technology will need to leverage spectrum at higher frequencies than current LTE technology. Moving to higher frequency spectrum will enable channel widths to move from 20MHz to 180MHz or more to offer greater speed, capacity, and overall performance. Licensed, shared licensed and unlicensed spectrum should be leveraged wherever possible to optimize the usage of available spectrum in any given situation.

Advancing the Internet of Things

With the internet of things (IoT) connecting an assortment of devices from smart meters, remote sensors, and autonomous vehicles; a wide variety of power, throughput, and other performance and cost requirements will need to be addressed. The development of 5G technologies will be necessary to serve the fractured and highly dynamic needs of IoT applications from one instant to the next and in the most efficient and effective way possible.

LTE is providing support for IoT applications during the largely nascent stages of their product life cycles. Applications which may need high throughput are able to benefit from LTE-Advanced technologies such as carrier aggregation, while many others will only need to transmit relatively small data payloads and be as power-efficient as possible to extend their useful lives in the field. Narrower bandwidth operation, half duplex mode, and single receive chains are some of the design elements which may be utilized in these low power IoT applications, providing benefits such as lower device bill of materials (BOM) cost and design complexity. LTE specifications such as Cat1, Cat0, and LTE-M all aim to enable lower power, complexity, and cost in IoT applications, but are evolutions of 4G architecture which was established more than a decade ago, before many IoT applications could even be considered. As the IoT continues to mature a new and more flexible 5G framework will be needed to truly optimize cost and performance requirements for the IoT from the start.

Improved Flexibility and Versatility

The evolution of voice to video calling, and immersive online experiences as well as the emergence of IoT is challenging mobile operators to increase the flexibility of their networks and improve throughput and efficiency while minimizing costs associated with these improvements. With the development of 5G, operators will want to use the best tool for any given case and leverage different wireless technologies such as Wi-Fi when appropriate. While the 5G OFDM waveform will be very different from that of the LTE OFDM waveform of today, continuing to base cellular technology on OFDM will help to ensure operators maximize their capital investment, while also allowing for the network to remain flexible to address the variety of applications which will rely upon it in the future. 5G technology, while still using OFDM as a basis, is envisioned to be scalable to wide bandwidths, doesn’t require complex receivers, and offers an existing framework for MIMO spatial multiplexing. A substantial amount of new design activity will have to take place at the physical (PHY) and media access control (MAC) layers of 5G networks and IHS will explore some of the benefits enabled by these techniques as part of this whitepaper.

It is clear that emerging applications will place higher demands on enhance mobile broadband capabilities and if the IoT market continues to grow at its current pace, cellular network performance will have to improve by an order of magnitude to address the new traffic coming online with a wide variety of throughput, latency, and reliability requirements which are sometimes contradictory to the requirements of mobile broadband use cases. In order for operators to stay ahead of future demands placed on their networks, 5G technology will have address the needs of both the mobile broadband market as well as the IoT market resulting in a wide range of benefits from new services and applications. Improved network operating efficiency from a cost and power standpoint will come as a result of the development of 5G technology; however design elements and many of the lessons learned in the development of LTE should be leveraged where possible.

In this whitepaper IHS will examine some of the techniques being assessed for inclusion in the 5G wireless standard. Techniques such as massive multiple-input multiple-output (MIMO) antenna designs, robust millimeter wave technology, multi-hop communications; resource spread multiple access (RSMA), and mission critical communications (MCC) will have to be used for operators to stay ahead of the future network demand curve.

Massive MIMO

The large volume of mobile handsets and particularly the growth of 4G-LTE enabled smartphones are driving the need for operators to provide a reliable and consistently high speed mobile broadband experience to end-users.

Massive MIMO will be one solution to cost effectively improving network performance. Through the use of antenna arrays, massive MIMO will improve RF propagation and enable the use of frequencies higher than 3GHz which offer larger channel widths than current LTE technology. With massive MIMO designs network operators could make use of existing macro sites to support frequencies higher than 3GHz, this could help minimize the number of small cell deployments required for improved network performance and reduce capital investment and operational costs.

The technology also enables networks to be more agile and accommodate constantly changing environments in real time by leveraging new design techniques. While the typical base station today may use a MIMO antenna design, the move to massive MIMO would increase the number of antennas by an order of magnitude. With Massive MIMO, base stations would employ antenna arrays with a large number of active elements, which could be optimized to improve signal transmission and reception. Some of the early massive MIMO designs employ 24x4 antenna arrays; achieving 80 MHz channel widths at a frequency around 4 GHz. The improved throughput from massive MIMO would depend on the surrounding environment; however a decrease in latency, improved power efficiency, and reduced complexity of the media access control (MAC) layer could also be potential benefits of the technology.

Robust Millimeter Wave Technology

Along with the aforementioned massive MIMO approach, operators can turn to robust millimeter wave technology to improve throughput, and make their cellular networks more reliable. In general larger bandwidths are realized at higher frequencies, with the trade-off being a more limited range. Products exists today which provides some foresight into the benefits of millimeter wave technology. 60GHz 802.11ad chips are currently being used for high data rate transmission over very short distances, enabling applications such as wireless display in notebooks, monitors, televisions, and mobile devices. Data rates with 802.11ad could reach higher than 6 gigabits per second (Gbps). Devices with 802.11ad capabilities began to ship in 2013 but are expected to experience extraordinary growth in the coming years as mobile handsets adopt the technology as well the aforementioned applications.

While 802.11ad works over very short distances of less than ten meters and in optimal line-of-sight situations of relatively fixed applications, 5G’s implementation of millimeter wave technology will utilize spectrum above 6GHz and could provide well over a hundred meters of coverage in environments with challenging propagation characteristics, such as indoor or highly reflective urban environments. To do this, robust millimeter wave will use line-of-sight and non-line-of-sight communication, using techniques such as directional beamforming. The technology will also be able to address the management of handovers and include a common scheduler to ensure packets don’t collide with one another. Thus, robust millimeter wave will optimize the user experience of mobile devices that require very high throughput relative to the rest of the mobile network, similar to the way users may turn to WLAN for faster speeds today, but with extended range capabilities providing for increased mobility. However, given that robust millimeter wave technology will be part of a mobile network, it will have to be designed in such a way that it is integrated with sub 6GHz frequencies to provide the seamless mobility and consistent mobile broadband performance that users have come to expect.

Robust millimeter wave will enhance the mobile broadband experience to enable faster, more responsive and more consistent user experiences. This enhanced mobile broadband (eMBB) will be required to address a very high volume of devices with large data payloads accessing the network, as applications such as virtual reality and ultra-high definition (UHD) or 4K video streaming will require very high data rates.

New use cases for 4K video are going above and beyond consumption for entertainment purposes, with services such as video medical consultations gaining in popularity. Although 4K video streaming isn’t yet a widespread and insurmountable challenge for mobile operators to address, smartphone cameras capable of 4K video capture have been on the market since 2013. As the installed base of these devices continues to grow, an increased volume of 4K content will be traveling across wireless networks. IHS anticipates that by 2019 there will be almost 800 million smartphones capable of 4K video capture shipping globally.

Smartphones with 4K displays have also become commercially available in 2015 with the introduction of the Sony Xperia Z5 Premium and IHS anticipates that the adoption of this feature in high-end smartphones will result in over 13 million devices shipping per quarter by the second quarter of 2017. 

On a longer term basis, IHS estimates that by the end of 2020 over 400 million 4K smartphone displays will have shipped. Robust millimeter wave technology will be a key enabler to an improved user experience for the upload and download of 4K video on the go, and the use of services which require streaming of a very high quality video connection.

Robust millimeter wave technology will provide a speed boost to all users on the network regardless of if they are actively using it. In current situations applications such as 4K video require network resources to the point that they can degrade service for other network users, but by those activities that require higher speeds moving to robust millimeter wave technology, network performance can be improved for all users.

Resource Spread Multiple Access

While technologies such as robust millimeter wave will provide a needed boost for mobile broadband situations, other low power IoT applications will not require the same high data rates, but will need a constantly reliable network connection available on demand.

Currently devices which need to communicate with the cellular network will have to request and be granted access to network resources making real time applications a challenge, especially when performance must be maintained for other network users. Opportunities exist for uplink RSMA non-orthogonal access using OFDM waveforms, and RSMA will be utilized in many 5G IoT applications as it allows for asynchronous grant free mobile access to support the uplink transmission of small bursts of data. This will essentially enable applications to communicate on an almost real time basis.

RSMA is usable for low bandwidth and low latency as well as high bandwidth low latency applications. However RSMA will be most beneficial to use cases such as environmental sensor networks or smart grid applications where there is a need to act on real time information immediately.

Multi-hop Communications

Cellular networks have traditionally employed direct communication between user equipment (UE) and the base station. However, as the focus shifts from voice communication to data transmission there is a need to ensure sufficient edge-to-edge coverage in a given cell. With the progression of the IoT many devices are able to download information from the wireless network, however depending on the application; their placement, and a limited power source there could be significant challenges in sustaining reliable uplink transmission. Multi-hop communications is one method of solving these uplink problems by allowing network clients to communicate with one another and act as managed relays to extend cell coverage; meanwhile the downlink remains a direct connection in order to manage the uplink communication and help make it secure. For instance a weather station at the edge of a cell may be able to communicate with a relay, which could send the data into the cloud for remote monitoring and analysis. While multi-hop communications is intended mainly for low power IoT applications, there could be more widespread consumer applications in the future. However, security issues provide a significant challenge for general consumer use.

Mission Critical Communications

Emerging IoT applications may require extremely low latency, a high order of reliability, or both to address applications which could use either large or small data payloads to maintain the safety of end users. For instance, although driverless cars remain in nascent stages of development, as they become closer to reality using technologies such as advanced driver assistance systems and automotive radar, next generation automobiles will need to maintain a reliable network connection for split second communications.

Other applications in transportation, public safety, power distribution grids, and gas and oil infrastructure need a high degree of reliability and extremely low loss rate, and 5G features such as mission critical communications (MCC) will be imperative. As with other aforementioned principles, MCC will need to rely on unified air interface design elements. The real-time nature of applications such as autonomous vehicles and robotics will require end-to-end latency an order of magnitude lower than current LTE deployments. New link adaptation methods with improved error correction processes and simultaneous redundant links will also have to be developed in order to ensure low latency and continuous reliability.

MCC could occur at any time and cannot wait for scheduling. The frame rate of non-critical applications will have to be punctured in order to allow for the sporadic nature of MCC.  Thus In order to achieve mission critical communications, networks will have to be designed in such a way that non-critical traffic can sustain the puncturing from MCC, likely while users remain unaware. New applications relying upon MCC will place strains on network capacity due to the low latency and increased reliability requirements, however this capacity challenge can be overcome through the use of wider bandwidths.

A Strong Foundation for Innovation

Current and future LTE technology is providing a sound foundation for the realization of 5G technology. Pioneering techniques such as using unlicensed spectrum, facilitating device to device communication, and using narrower bandwidths to simplify design and cost requirements for IoT applications are indicative of the evolution to the next generation of wireless wide area communication technology. 

5G technology will usher in new service opportunities for mobile network operators (MNOs), but new business models will emerge as well. 5G networks will be employed by a variety of entities in the future, from MNOs, to large venue owners, internet service providers (ISPs), and in enterprise and small office or consumer environments. During the development of 4G technology the core network configuration was enhanced over time, with each improvement creating more complexity and requiring changes to the existing network architecture to accommodate evolving use cases for end-devices. 5G technology will aim to separate core network functionality to allow for a more adaptive approach to the newly enabled business models and various applications of the future.

As the standardization process of 5G technology begins, it is important for policymakers to recognize the benefit of advancing a unified communications standard which is not dependent upon a single technology or technique to address the needs of the varying markets which will comprise the mobile ecosystem of the future. Design elements such as Wi-Fi, OFDM, massive MIMO, robust millimeter wave technology, resource spread multiple access, and mission critical communications could all play their part in the execution of 5G. While the final time-line of 5G deployments remains to be seen, it is clear that in order to achieve the thousand fold increase in capacity that may be required to address tomorrow’s use cases and applications effectively, operators will need to turn to innovative network design and deployment techniques.

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