Vendors elaborate on LTE-A test

Our May print edition includes a special report on LTE-Advanced (LTE-A), which represents the next progression in the long-term evolution of the 3GPP's cellular communications standards. LTE-A emphasizes features such as carrier aggregation (CA) and multiple-input, multiple-output (MIMO) techniques to provide higher bit rates while maintaining compatibility with earlier cellular implementations.

Since that article went to press, vendors including Aeroflex, Agilent Technologies, Anritsu, Bluetest, GL Communications, and Spirent Communications have introduced new products or enhancements that address LTE and LTE-A test. The new offerings address technologies ranging from MIMO, which makes use of multiple antennas at both the transmitter and receiver to boost data rates, to CA, which supports higher bandwidths.

Spirent, for example, announced its collaboration with Bluetest to deliver an integrated test solution for MIMO over-the-air (OTA) throughput testing. Spirent reports that although standards bodies are still defining MIMO OTA test standards for the industry, leading operators are moving ahead and requiring conformance to their MIMO OTA test plans now.

“Our close partnership with Spirent was a deliberate move to produce the most dependable and comprehensive MIMO OTA test system in response to leading operators’ MIMO OTA test requirements,” said Kjell Olovsson, Bluetest CEO. “Spirent’s VR5 Channel Emulator integrated with our Reverberation Test System allows us to create a wider range of reference environments in the lab and accurately validate LTE data throughput under challenging MIMO conditions.”

Spirent reports that the performance of MIMO is especially sensitive to a wireless device's system design because of the many interactions between antennas, case, RF modules, chipsets, and firmware. OTA testing is where these interactions first become apparent and where designers really start to see the full system performance. The reverberation chamber provides a dynamic free-space reference environment upon which wireless channel emulators apply real-world spatial channel models. This enables the user to precisely characterize how well a mobile device with MIMO receives signals and operates in an environment with these real-world spatial properties.

“Being first to apply the reverb chamber to wireless testing, Bluetest is well recognized as an industry leader in OTA testing methodology,” said Dave Garrison, Spirent’s senior director of wireless product development. “Bluetest’s years of experience deliver a higher degree of accuracy and reliability, and [its] selection of Spirent’s VR5 Channel Emulator confirms our shared commitment to support the industry’s urgent need to validate MIMO performance on next generation devices.” 

The MIMO OTA solution integrates Bluetest’s RTS60 Reverberation Test System with Spirent’s VR5 Spatial Channel Emulator.

Spirent also announced that China Mobile’s research division, China Mobile Research Institute, has selected Spirent Landslide to verify the performance of its Evolved Packet Core (EPC) network. This selection follows China Mobile’s purchase of Spirent Landslide to test its 3G packet core.

Spirent Landslide will enable China Mobile to model user behavior and create traffic over the control and data planes by emulating real-world calls from millions of smartphones. “Spirent Landslide’s integrated test cases and GUI-based automation allow engineers to quickly model carrier specific subscriber behavior at extreme scale,” said Ross Cassan, director of product marketing at Spirent. Spirent Landslide, he said, will allow China Mobile to ensure that the mobile core network delivers a high quality of service while accommodating growth in new subscribers and traffic. In addition, Landslide will help resolve issues in China Mobile's multivendor ecosystem.

Aeroflex demonstrated its continuing commitment to LTE technology with its recent announcement that the TM500 LTE-A Test Mobile and the E500 Capacity Test System (Figure 1) now both support the aggregation of three component carriers (3 CC). Carrier aggregation of 3 CC allows mobile network operators to achieve data rates of up to 450 Mbit/s on their LTE-A networks.

3 CC carrier aggregation enables network operators with limited contiguous frequency allocations to maximize 4G data speeds by combining these spectrum bands. Network operators can use the E500 Capacity Test system to prove that new network features such as 3 CC aggregation deliver as promised on their networks. The new 3 CC capability builds on the TM500's two years of support for the development and test of LTE-A carrier aggregation.”

The TM500 Test Mobile is the first commercial infrastructure test platform to release 3 CC,” said Shusina Ngwa, product manager at Aeroflex. “Offering this capability at such an early stage is crucial to enable network performance to be tested and validated, ahead of the availability of end-user terminals and handsets.”

Aeroflex’s LTE product line includes a complete range of end-to-end test systems that cover R&D, performance, service, and manufacturing test applications for LTE-A TDD and FDD network equipment and terminals. Aeroflex is also a founding member of the 5GIC (5G Innovation Centre) technology research program led by the University of Surrey in the UK.

For its part, GL Communications Inc. has announced the release of its enhanced Voice and Data Testing Solutions: VQuad, WebViewer, and Mobile Device Controller, which supports LTA and other communications technologies. Robert Bichefsky, senior manager, product development, said, “As advanced technologies such as LTE, Advanced LTE, WiMax, 3G, and broadband are becoming common, basic voice/data quality will ultimately determine the fate of carriers and end equipment manufacturers. Simple and effective methods of testing voice and data are basic requirements. GL's mobile test solution provides this capability with the flexibility of connecting to and between any network, any service, and any interface.”

Anritsu also expanded its offerings with LTE applicability. The company announced it has developed the wireless industry’s first PTCRB-approved protocol test case for IMS Emergency Services. This critical test case is now available on the ME7834L Protocol Conformance Test (PCT) and Carrier Acceptance Test (CAT) system (Figure 2). Anritsu recently became the only supplier of approved test cases for this increasingly relevant technology during the PVG#64 meeting held in Beijing.

The IP Multimedia Subsystem or IP Multimedia Core Network Subsystem (IMS) is an architectural framework for delivering IP multimedia services. It was originally designed by the 3rd Generation Partnership Project (3GPP) as a part of the vision for evolving mobile networks beyond GSM.

Test cases for emergency services over IMS have been identified by the PTCRB as part of “Request for Testing” (RFT) 097 requirements. The GCF has defined similar requirements as part of Work Item (WI) 154.

Anritsu’s IMS Emergency Service test case support further adds to the test capabilities of the ME7834L Protocol and Carrier Acceptance Test Platform. The Anritsu ME7834L also provides device certification solutions for VoLTE and SMS over IMS. As LTE network deployment increases, it is expected that IMS will become an important VoLTE service, as it provides a lower price point.

“Anritsu continues to demonstrate its position as a market-leading conformance test provider. The approval of the IMS Emergency Services test case reinforces our commitment to provide test solutions that allow device manufacturers to bring leading-edge products to market with confidence. Our goal is to provide customers with the broadest test capabilities as defined by the GCF and PTCRB, as well as Carrier/Operator-specified test requirements,” said Wade Hulon, senior vice president and general manager of Anritsu Company.

The ME7834L scalable GCF- and PTCRB-validated test system enables certification of LTE devices to industry and carrier standards. Test coverage is available for 3GPP 36.523-1 (Protocol), as well as global operator-specified acceptance test package requirements. The ME7834L can also be configured as a customized integrated environment for InterRAT tests between LTE, GSM, W-CDMA, CDMA2000, and TD-SCDMA mobile systems.

Furthering its LTE-capable offerings, Agilent Technologies announced an enhancement to its Passive Network Monitoring System for converged telecommunication networks across 2G, 2.5G, 3G, and now 4G LTE technologies (Figure 3).

Agilent’s Passive Network Monitoring Systems offer a scalable monitoring and processing portfolio that processes both voice and data independently of the telecom network elements. These systems allow legally authorized users to identify and extract communications of interest and provide accurate location information, correlate voice and data selectors, and provide advanced filtering and selection for multiple 10GbE and legacy communications links.

“10GbE is rapidly becoming the default interface on 3G and 4G network equipment,” said Tom Burrell, vice president and general manager of Agilent’s Signal Networks Division. “The addition of 10GbE and LTE to our portfolio ensures that our customers can continue to expand their coverage as communication networks continue to evolve and converge.”

Agilent Passive Network Monitoring Systems are based on a high-availability 2U industry-standard platform. A flexible API with an extremely wide range of selection triggers and filters enables integration with multiple network management, lawful intercept, geolocation and cyber defense applications. High levels of security procedures and protocols ensure that only authorized users gain access to warranted information.

In addition, Agilent released a new RF power amplifier test reference solution, which supports the testing of devices that utilize envelope tracking for improved power efficiency, providing an advantage for LTE-A power amplifier-developers. Visit here for more.

And finally, Agilent is also offering three new videos on LTE-A technology and test challenges:

• End-to-End IP data throughput, with/without channel impairments, using E7515A UXM wireless test set
• DL channel configuration flexibility for LTE receiver testing using E7515A UXM wireless test set
• How to perform CSI measurements using E7515A UXM wireless test set
• To view the videos, visit www.agilent.com/find/CellularVideos. Registration is required.