September 19, 2017
The recent decision by the 3GPP during its meeting in Croatia to move the schedule for 5G standardization up six months was welcome news to carriers, chipset makers, device manufacturers and others in the wireless industry. It not only keeps 5G on schedule for 2020, it may have even escalated the rollout to sometime in 2019. Furthering the notion of a closer 5G horizon is that 36 operators worldwide have begun pre-standardized trials, all with the goal of launching the next generation of wireless technology sooner rather than later.
The first 3GPP 5G New Radio (NR) specification will be part of Release 15, scheduled for release before year’s end, and will focus on Non-Standalone (NSA) 5G. NSA will leverage existing LTE networks but will also rely on high-frequency millimeter waves (mmWave) between 28 GHz – 38 GHz. The integration of these bands will place various pressure points on base stations and how they are going to be used. Because of this, field engineers and technicians need to understand how the first phase of 5G will be deployed and how to properly test it to achieve established key performance indicators (KPIs).
NSA Architecture
NSA will utilize existing LTE radio and the evolved packet core network as an anchor for mobility management and coverage. It will also add a new radio access carrier to enable certain use cases, primarily fixed-wireless broadband. Core mobile device actions, such as scheduling and handovers, will be conducted using the LTE channel to leverage its broader coverage.
Data capacity – along with lower latency and longer battery life – is a key selling feature of 5G. These promised high-bandwidth services at faster speeds will require a broader pipe than the 20 MHz bandwidth LTE can provide. That is where mmWave technologies come into play. With aggregated channel bandwidths of 1 GHz and higher, mmWave frequencies will deliver on the promise of 5G.
Macro Cells and Small Cells Importance
Because 5G is meant to augment 4G, both macro cells and small cells will play key roles in the pre-standardized period – as well as the 5G NR initial phase. Existing macro cells will be used for the LTE elements. Many existing base stations have been upgraded to incorporate technologies such as C-RAN and CPRI to make for a smooth transition to 5G.
Small cells, which are low-powered radio access nodes that can be installed in short increments due to their compact size, have become a critical part of wireless networks. They have proven to be an excellent method to provide capacity in areas where it’s difficult to build macro cell sites, particularly urban geographies. While small cells have been initially used for LTE networks, they will gain new prominence in 5G, as they will be an effective means to compensate for the short range of mmWave signals.
Testing Procedures
5G trials and ultimately the official deployment of the next generation technology will require test procedures similar to today’s processes. As is the case currently, limiting interference will be vital in 5G, as the high-bandwidth services will have much more stringent requirements because the slightest effect on a signal can have demonstrative results. Key measurements will remain channel power, occupied bandwidth, return loss, passive intermodulation (PIM), and adjacent channel power ratio (ACPR). The integration of fiber into these networks also mean traditional optical measurements, such as OTDR tests, must be conducted on both the fronthaul and back haul.
A big difference as it relates to testing is going to be in measurement accuracy. Interference hunting requires the ability to spot, find and fix a known interferer as quickly as possible so 5G networks meet KPIs. Accurate measurements can help locate a problem faster, saving valuable time and money. To achieve this, operators and those responsible for network performance and maintenance will need a full portfolio of interference tools.
Remote spectrum monitors are a cost-efficient method to observe network performance 24/7/365 and send alerts when performance dips below pre-determined thresholds. When those instances occur, solutions such as the Mobile Interference Hunting System can quickly and reliably locate interfering signals from a moving vehicle, even when there are multiple sources.
Handheld test instruments, such as the BTS Master™ MT8220T, that combine the measurement capability of 30 instruments can be used for an interference hunt, as well. Often, it is used with the Handheld Interference Hunter MA2700A that features a GPS receiver and antenna, electronic compass, and user-selectable preamplifier to help expedite locating and correcting interference issues. Utilization of all these tools will help keep 5G networks operational, just as they are accomplishing the task today.
To learn more about interference and test solutions to quickly and efficiently locate their sources, visit this educational interference hunting webpage.
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