Need for Field Testing to Continue to Grow
By Jessy Cavazos, Industry Director, Test and Measurement, Frost & Sullivan

Nowadays, much of the talk in field testing revolves around Long Term Evolution (LTE). Ongoing deployments of LTE will keep field technicians, both from network operators and contractors, busy for the next couple of years, till LTE Advanced (LTE-A) comes into the picture. While LTE-A will bring a new set of challenges in the field, likely to take the challenges being faced today up a notch, we have not yet seen all of what LTE will bring. Indeed, issues may not have appeared yet as it is not a widely accepted network. While there are good guesses about what these issues will be, we won’t really know about them until wider deployment occurs. Current challenges are significant enough and the focus of this article.

Navigating the Multi-Technology Environment
Wireless technologies up to LTE are relatively mature and the instrumentation for it has not changed dramatically recently. However, LTE is a very different technology and, while from a user perspective it may look the same, it is increasing the complexity of the network and making it a lot less tolerant to faults. With tighter specifications and less tolerance to faults, field technicians may need additional tools to identify these faults. In addition, field technicians are wondering about what they need to focus on now as opposed to what they were focusing on with older transmission technologies. There is a need for education, as contractors want to understand the network at a high level, its complexities, the challenges it brings about, and the difference in the measurements they need to make now as opposed to then.

Although technicians’ key concern is LTE today, it is only a subset of the real challenge that is the multi-technology environment they operate in, one that is only expected to increase in complexity in the future, as depicted in Figure 1. The ability to rapidly assess system performance in a multi-technology environment is no easy task. Moreover, the pace at which new wireless technologies go through the life cycle from the laboratory to the field is increasing. LTE and LTE-A will certainly lead to a need for new equipment and types of tests, specifically once the handsets are used in the market. With intelligent devices able to take over some of the control from the towers, self-managed networks will require more sophisticated test equipment.

The increasing complexity of network equipment is bringing about new challenges to technicians. Specifically, new remote radio head (RRH) technology is adding a level of complexity to the environment in which field technicians evolve. Making measurements has become more difficult as the physical access to the connections and antenna components is limited. Technicians’ ability during antenna installation and maintenance to go directly to the base station, connect into the cabling, and verify if the infrastructure piece of the base station is the source of the problem they see is much more limited. As a result, over-the-air testing has increased in importance so as to determine if the network is working properly.

Interference Issues on the Rise
Another issue rising from the increasing complexity of network and network equipment is interference, which can come from a variety of sources, both internal and external. In order for these new network technologies to work properly at maximum performance, the radio frequency (RF) environment needs to be as clean as possible.

When assessing the network performance, technicians need to ensure that the RF environment is interference-free so as to ensure optimum user experience. There are a number of sources that can cause RF interference and impact user experience, one of which is cable television (TV). “That’s a very big hurricane that’s coming,” says Joe Gallagher, Business Development Manager for Network Operators at Rohde & Schwarz USA, Inc. “Up to now, cable operators have not necessarily looked for 700 MHz egress or ingress because they did not have any pending issues. Now that the network operators have taken over that spectrum from broadcasters, if there is some type of RF interference, the network operator can in theory increase the power level of the base station, but from the mobile device perspective, it is transmitting at such low power that if there is any interference that is coming in those same frequency ranges, it can have a huge impact on user experience.” Because LTE is a closed loop environment, the mobile device reports back to the base station the signal quality that it is receiving from the base station. If the signal does not get back to the base station, the base station could think the mobile device has gone quiet and may terminate the connection, impacting user experience. Interference can have a huge impact on new next-generation technologies. To ensure optimum user experience, the RF environment needs to be as clean as possible.

While the issue of interference is not new, it has taken a whole new meaning with LTE. The importance of both external and internal interference issues has soared. With external interference issues, a major challenge for technicians is to figure out the source of the issues. With consumers installing bidirectional amplifiers in their homes illegally to get stronger signals and the proliferation of femtocells, which act like mini base stations, the sources of external interference issues have grown. Research published by Frost & Sullivan earlier this year indicates that this is likely to continue, with unit shipments for the femtocell market expected to reach 12.9 million globally by 2013.

From the internal interference perspective, the issue of passive intermodulation (PIM) has also grown. While one may assume it is easier to locate the source of a PIM issue than that of an external interfere (because it is somewhere in the cabling), it is still a significant challenge for technicians, with many tools in the market telling the user they have a problem, yet not telling the user where it is. With the industry investing billions of dollars in next-generation network infrastructure rollouts and expected to invest even more over the next 3-4 years, PIM testing is becoming a mandatory part of the testing that needs to be done at a cell site. PIM issues can be costly, resulting in dropped calls, lower revenues and unhappy subscribers. The industry cannot afford to jeopardize the investments it has made and will make with PIM issues.

As more frequencies and data are being put in the same pipe, the intermixing of RF signals is translating into a diversity of issues on the base station. Further, while towers have always been subject to passive intermodulation due to rusty bolts, loose cables, etc., with the new network, it creates interference outside the network such that the base station or the switching equipment cannot differentiate it from a signal coming from a handset. As the technology becomes more complex, interference becomes more of a challenge, and an issue that field technicians need to watch out for.

Test equipment vendors offer purposely-built equipment that address interference challenges; equipment that is portable and battery-operated. They also offer equipment that enables users to catch even fast, intermittent types of interferes. An example is the PR100 portable receiver from Rohde & Schwarz that can be used to catch very short cycle RF transmitted signals. For PIM, analyzers are available from vendors such as Anritsu, Summitek Instruments, Communication Components Inc. (CCI), Rosenberger Hochfrequenztechnik GmbH & Co KG, and Boonton Electronics. “Cellular operators don’t just need PIM testing,” highlights Nick Cannon, Product Manager for the Microwave Measurement Division at Anritsu Company. “They need performance measurement tools as well. At Anritsu, we strive to provide the complete solution for the performance of a cellular site. The MW8219 plugs into our handheld instruments, such as the BTS/Cell Master, so that technicians can perform all sorts of performance measurements.”

Need for Economical Solutions
Beyond technical issues, other factors translate into significant challenges, specifically for contractors. One such challenge is the sheer number of them, making winning the business difficult. To that end, they need to comprehend all that is required to win the opportunities available to them, including the cost of resources, access to personnel, and the type of test equipment needed. Thin margins are compounding these aspects, making the review of test equipment acquisition options critical. Contractors need to investigate the various financial options at their disposal and select a financial solution that matches their needs. This is of utmost importance for contractors since they work on one project for one network operator one month and another the next. Another key concern is time, which is also an aspect that needs to be factored in the decision when acquiring test equipment.

Due to the changing nature of the contracting business, and that of the wireless communications industry, one attractive financial solution for contractors is renting or leasing the test equipment rather than purchasing. Major test equipment manufacturers work with rental and leasing test equipment companies like Electro Rent Corporation and Continental Resources, Inc. (ConRes). “In addition to ensuring the availability of the equipment, we go the extra mile by making sure the equipment is somehow over-optioned to ensure that if there is a remote test set not used very often, it is included. Our understanding of what is generally specified by carriers and network equipment manufacturers helps us in this regard,” says Bob Tate, Director at Electro Rent Corporation. “Moreover, connectors, cables and ancillary items that are required to make the measurements are not always covered in the procedures. Working with a test equipment provider that has knowledge of the specifications can help contractors get the job done more efficiently.”

At the same time, test manufacturers have increased their focus on total cost of ownership (TCO) and continue to focus on increasing the value of their equipment. Another compelling solution for contractors is the availability of used equipment. Some test equipment manufacturers offer refurbished equipment with the same level of warranty and service as a new unit, yet at a much lower price. This resonates well with contractors whose price sensitivity is exacerbated by paper-thin margins.

Increased Demand for Simplifying Testing
The complexity of the network and network equipment, including base stations and mobile devices, has increased tremendously. Some mobile devices out in the market integrate different technologies such as LTE, Global System of Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), Wireless Fidelity (Wi-Fi), etc. at different frequency bands, including 700, 800, 850, and 1900 MHz. The complexity of such devices is much higher compared to just a few years ago, when they only featured GSM and Enhanced Data Rates for GSM Evolution (EDGE) at 850-1900 MHz. There is a similar trend on the base station side. The base stations used in Sprint’s next-generation network architecture rollout, for example, will have the ability to do Evolution-Data Optimized (EV-DO), Code Division Multiple Access (CDMA) 2000, Time-Division Long-Term Evolution (TD-LTE), Worldwide Interoperability for Microwave Access (WiMAX), and Frequency-Division Long-Term Evolution (FD-LTE) all in the same chassis. As the technology becomes more sophisticated, and the pace at which they are being implemented in the network increases, installers simply can’t keep up. As a result, test equipment manufacturers need to find ways to simplify the testing that needs to be done at the base station; one such means is test scripts. Demand for simplifying testing and therefore automation has grown tremendously recently. While test manufacturers have become much better at quick start user guides, research indicates that there is still room for improvement. Such demand is coming from all field technicians but is of particular importance for contractors due to the changing nature of their business. The impact of this challenge for network operators’ technicians is slightly reduced as they tend to work on the same technologies. Additional benefits of test scripts include reducing the potential for errors and ensuring consistency across geographic areas. Last but not least, it also introduces accountability.

Conformance Testing in the Field
While the increase in complexity of networks and related equipment brings about a variety of challenges for field technicians, it also translates into better opportunities for testing, one of which is conformance testing. While a lot of conformance testing is being done in a lab-controlled environment, there is a need to bring devices out in the field and see how they operate. Contractors may have an opportunity at hand with over-the-air testing, using drive test tools to see how many devices operate interactively in a network. Because of the way the devices work, over-the-air and interoperability testing that used to be performed in the lab is expected to move out to the field.

Final Word
As new technologies become more mainstream, the requirements and the expectations that the devices being used by consumers are meeting certain technological aspects increase. Network operators have spent billions of dollars on the 700 MHz spectrum and are going to spend much more to develop and support that infrastructure over the next few years. With shareholders on the lookout for high returns on their investments, the need for testing in the field is not going away anytime soon.

Frost & Sullivan

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