The arrival of Long Term Evolution (LTE) brought significantly different wireless network capabilities. Today’s wireless user wants and expects superior service and performance. To make sure this happens, extensive and frequent network testing needs to be done. And when it comes to LTE testing, nothing can be spared. Plus, with the quality expectations of mobile users on the rise, service providers need to know their network infrastructure can handle burgeoning traffic loads and ever-more-complex application traffic without compromising performance or security. This type of testing, however, can become extremely expensive and inconvenient. Wireless network operators must find innovative, and affordable ways to test their networks, as it will become more and more part of everyday life.
Successful LTE deployment depends on the compatibility and effective inter-working of the system’s different elements. Conformance LTE testing, according to Agilent, ensures that those specific elements meet a minimum level of performance as defined in the 3GPP specifications. The LTE conformance tests also cover base station, user equipment, and radio resource management performance. They are a major focus of vendors today who are developing LTE network and user equipment.
LTE air interface is extremely complex and supports many options for modulation format, frequency bands, resource allocations, and mobility. Because of this, the number of RF configuration permutations that can be tested is enormous. When selecting RF configurations for the LTE conformance tests, 3GPP identified combinations of parameters representing the most difficult operating conditions, so when a product passes the tests, it can be assumed the device will perform satisfactorily in many other, less-challenging scenarios.
Although the lists of conformance tests seem daunting, additional tests are still needed on top of that. “For example, closer investigation of performance margins is important since conformance testing gives only a pass/fail result with no indication of how close the product is to a particular limit. LTE conformance tests are designed primarily to ensure that the network’s underlying transport mechanisms can carry end-user services, so higher level applications still need to be tested. Operator acceptance testing is yet another step in the process and includes more user-centric tests. Thus the conformance tests represent an essential step toward LTE deployment, but they are neither the beginning nor the end of the test process.” [1]
When it comes to LTE testing, however, there are many different methods. For 4G LTE access networks in particular, carriers must optimize use of new eNodeB radio base stations critical to improving and sustaining spectrum efficiency, capacity, data rates, and end-user quality of experience (QoE) for mobile subscribers, as reported by Ixia. “The eNodeB performs radio resource scheduling and uplink/downlink rate limiting to enforce policy decisions and QoS characteristics associated to different service and subscriber types on the network.”
Wireless network providers who are currently rolling out Long Term Evolution (LTE) and 4G networks in particular must efficiently and accurately test mobile infrastructures under punishing real-world conditions—without spending a ton of time or money to do it. eNodeB testing involves validating multiple levels, including:
- Physical, protocol, and application layer functionality
- Security and handover performance
- User and control plane capacity and throughput
- Policy management and QoS mechanisms for converged voice, video, and data traffic [2]
LTE testing is no joke, nor should it be taken lightly. These networks and their accompanying performance levels are serious, about as serious as the wireless users who demand perfection.
[1] Agilent Technologies, Long Term Evolution – LTE Test, http://www.home.agilent.com/agilent/application.jspx?cc=US&lc=eng&ckey=1174746&nid=-34867.0.00&id=1174746&cmpid=20331
[2] Ixia, 4G LTE Testing, http://www.ixiacom.com/solutions/lte-testing/
