Case Studies from the Real World
Azimuth Systems is a leading provider of wireless test solutions for Wi-Fi, WiMAX, and 4G wireless technologies like LTE and 802.16m. Azimuth's test solutions are used by the world's foremost wireless semiconductor, device manufacturers, infrastructure vendors, and service providers to speed time-to-market and improve wireless IP performance. Azimuth's test solutions simplify laboratory performance and certification testing of mobile IP devices and networks designed to support data, voice and video applications.
Successful delivery of converged services is based on an assumption that wireless IP networks and devices can deliver seamless quality of service (QoS) to the customer. Such converged services—based on LTE, 3G UMTS, WiMAX, and Wi-Fi—are designed to deliver IP voice, video, and data over the air to a wide array of wireless client devices. End-user satisfaction is based on meeting QoS expectations, and service providers consistently meeting those QoS expectations will be the long-term winners. Azimuth Systems works closely with leading service providers to qualify their infrastructure and subscriber devices predeployment in internal validation/certification labs to ensure quick, reliable and cost effective deployment. Performance benchmarking is the basis of selecting the highest performing infrastructure and mobile IP devices and counteracting the often manual, ad hoc methods used by many manufacturers in the equipment supply chain. Interoperability testing is central to the service providers offering diverse subscriber solutions that work well on their network and also roam to supporting networks.
Service providers deploying or assessing wireless IP technology use Azimuth's test solutions to:
- Validate the fundamental capability of broadband wireless to deliver voice, video and data QoS over the air.
- Measure the effect of motion and range on performance and stability of voice, video and data traffic and set thresholds for “carrier grade” performance.
- Perform a wide array of standardized, automated performance benchmarking on both infrastructure and client devices in virtually all possible modes of configuration.
- Correlate results with equipment suppliers.
- Perform ongoing validation to ensure that operation will not be impacted by software upgrades or by the introduction of new devices.
- Reduce the time associated with qualification of new devices and infrastructure equipment.
Azimuth Service Provider customers include the world's leading broadband, cellular, and FMC operators. The following examples illustrate the circumstances our service provider customers have encountered in testing their products and the successful outcomes Azimuth has enabled.
These real-world examples include brief customer profiles and the testing challenges met with Azimuth solutions, while preserving the anonymity in each case.
Major US Service Provider rolling out a WiMAX network.
- Design and build out the network to support the performance and capacity expected.
- Validate advanced functionality of network equipment is fully functional.
- Certify performance and compliance to specifications of the network infrastructure and devices which will be sold to operate on the network.
- Test interoperability of infrastructure and user devices from chosen vendors.
- Once the network is operational, maintain and grow the coverage and user base cost effectively.
- Build network specific certification/acceptance program for handset and user devices proposed for deployment.
- Reduce the time required to qualify new infrastructure or user devices.
- How well will the network perform in real-world wireless conditions?
- Does the network offer the performance and seamless handoff users expect?
- Do handsets and data devices work well together on the diverse network?
Suppliers, test equipment vendors, and lab partners are working together to define, validate, and run a series of tests to address the challenges faced by the vendor. Once the test cases are defined and validated, pairs of infrastructure and mobile device vendors work together to produce performance and interoperability results. In parallel, the test equipment vendors and lab partners are working to develop test automation and standard test beds. The lab partners will perform these tests for all new vendors and equipment that will be proposed to add to the network in the future.
Core to the testing in the lab is the ability to re-create a real-world repeatable scenario to run these tests. The service provider has built a comprehensive test solution to test “carrier grade” WiMAX that includes Azimuth's ACE channel emulator. The test plan includes the following applications:
- Point-to-point performance test scenarios using Azimuth ACE to re-create real world channel conditions.
- Interference tests where the effect of radio noise is evaluated using the ACE's AWGN noise generation capabilities.
- Testing of advanced antenna solutions (e.g., the use of spatial multiplexing to increase throughput) and antenna diversity (e.g., STC and MRC to improve transmission reliability) over an emulated channel environment provided by the ACE.
- Multiple link testing involving multiple base stations or multiple subscriber stations to validate correct operation of functions like handoff for seamless operation and collaborative uplink for enhanced throughput.
- Interoperability testing that relies upon the ability to re-create identical but stressful real-world conditions for multiple different devices to be tested for consistent performance and feature delivery.
- Range analysis vs. performance in multiple “impaired environments.”
Azimuth has worked closely with vendors and service provider to provide guidance in the design and configuration of the test cases and their implementation. Azimuth is supporting the automation efforts to turn the finalized test cases into fully automated test procedures that can be run from a central test executive on demand.
One of the world's leading wireless service providers
- Validate capability of unlicensed mobile access (UMA) service delivery.
- Benchmark handset and access points for deployment selection.
- Reduce the time required to qualify converged cellular/Wi-Fi handsets.
- How will voice over Wi-Fi voice quality be affected by range?
- What access points provide the highest QoS and the greatest real-world range performance? How does performance vary based on interoperability with various handsets? How will voice over Wi-Fi voice quality be affected by background data traffic?
- How are the performance characteristics affected by multipath impairments? How will real-world voice over Wi-Fi performance vary in relation to customer dwelling?
- How will voice quality be affected during the cellular to Wi-Fi handoff process?
- What impact does Wi-Fi have on standby time and talk time?
The service provider built a comprehensive test solution to test “carrier grade” Wi-Fi using Azimuth's W-Series test platform and FMC Performance Test Suite. The test plan includes the following applications:
- Azimuth's automated throughout vs. range test solution delivers simple, repeatable analysis of the impact of range on voice quality.
- Azimuth's access point performance test solution delivers the ability to measure the access point's capability to prioritize traffic based on QoS priority. The test solution can automatically increase both the number of background clients and the upstream/downstream traffic load to each client.
- Azimuth's ACE Channel Emulator automates the capability to perform range analysis in multiple “impaired environments” that conform to standard or customer generated channel models. The combination of ACE and Azimuth's STUDIO™ test data management software, allows for automated measurement and analysis of voice or data quality anomalies that are related to varying channel conditions caused by multipath and/or physical layer interference. Azimuth and the customer are cooperating to use real-world analysis and results to develop channel models that are representative of a wide array of customer dwellings to increase predeployment test coverage while reducing the need to run tests in the real world.