Spirent Communications, Inc.

The technology disclosed concerns a method, system, and computer media for self-calibrating a test environment to replicate path loss between wireless devices in a model environment despite Over the Air coupling uncertainty. The test environment has a controller and test chambers holding wireless devices and connected by connective cables fitted with attenuators and measurement devices. For a pair of test chambers, the controller causes generation of first and second reference signals to be transmitted over a respective cable, to and from the held wireless devices. The controller receives, from the respective measurement device on the respective connective cable, measurements of the first and second reference signals. The controller sends configuration signals to the respective attenuator based on the measurements of the first and second reference signals, causing the respective attenuator to reproduce path loss in the model environment between the pair of signal sources.

The technology involves a method, medium, and testbed scoring cloud-application Quality of Experience (“QoE”) by emulating a mesh network at building locations inside of a building. The testbed includes test environment devices comprising test chambers holding respective stations (“STAs”) that run applications, or Access Points (“APs”) coupled in a mesh, respective connective cables between pairs of test environment devices, the cables reproducing attenuation between building locations, and at least one of the APs serving as a gateway to an internet server. QoE scoring includes a controller causing multiple types of applications on the STAs to generate traffic by executing test exchanges with the server. The testbed measures traffic produced by the test exchanges and scores the traffic streams measured for each of the test sequences of exchanges by combining the measurements into traffic stream scores and by combining the traffic stream scores for the application into a cloud-application QoE score.

The technology includes a method, computer medium, and system for testing audio quality of a transport segment between two core networks. A first virtual test agent (VTA) selects a Mobility Management Engine (MME) corresponding to an eNodeB served by a first core network for routing a second call, through a Serving Gateway (SGW) assigned by the MME for audio communication with a tester terminus. The second call is made from the first VTA to a second VTA at a second core network over a transport-segment-under-test that connects the first and second core networks, So that a tester can evaluate audio quality over the transport-segment-under-test. The first VTA makes a first call to a tester appliance, makes a second call, over the transport-segment-under-test, to the second VTA implementing audio evaluation, by signaling the MME, and bridges the first and second calls by relaying audio during a test of subjective audio quality.

The technology includes a method, computer medium, and system for testing transport audio quality irrespective of tester location. The technology involves a virtual test agent (VTA) selecting a Mobility Management Engine (MME) for routing a second call through a Serving Gateway (SGW) assigned by the MME for audio communication with a tester terminus over a transport segment under test, so a tester can evaluate audio quality over the transport segment under test. The VTA makes a first call to a tester appliance, and makes a second call, over the transport segment under test, to the tester terminus by signaling the MME. The VTA bridges the first and second calls by relaying audio during a test of subjective audio quality, whereby the bridging assures that the relayed audio in the second call continues to be relayed over the transport segment under test and not re-routed by core network components.

The technology disclosed teaches a system and methods for end-to-end self-calibration of a channel emulator, wherein the channel emulator includes at least one channel emulator signal chain and at least one integrated parallel calibration signal chain. The channel emulator signal chain further includes an input signal, a first signal conditioner, a first analog-to-digital converter, a baseband processor, second signal conditioner, and an output. The integrated parallel calibration signal chain further includes a sequence generator, wherein the sequence generator is configured to generate a pseudo-random sequence upon which a calibration analysis signal is overlayed. On the supplying side, the sequence generator is coupled to a second digital-to-analog converter for supplying the calibration analysis signal to be processed by the channel emulator signal chain. On the evaluating side, the sequence generator is coupled to a comparator for evaluating results of the processed calibration analysis signal.

The disclosed technology teaches systems and methods for high fidelity emulation of a Wi-Fi environment for testing with three or more transmitters set to differing output signal strengths. The disclosed method includes using a PCAP file of captured packets from multiple stations with respective source addresses, RF bands, and channels within bands. The captured packets record metadata containing, at least, signal strength and time stamps. The method further includes analyzing the PCAP file to determine pairs of source addresses and channels, evaluating the pairs for signal strength, and allocating the pairs to three or more transmitters based on grouping by at least the channels and the evaluated signal strengths, and using the time stamps on the captured packets, replaying with synchronization over the transmitters at the set output signal strengths. The PCAP file can include packets from multiple protocols, and time-varying pairs with varying signal strength over time.

A method for determining whether clock skew may exist between a sending node and a remote node during two-way network testing (using protocols such as TWAMP), and a computational method for revising measured latency data to compensate for clock differences. The method for compensating for clock skew comprises monitoring the network latency between two nodes during a defined time interval. When clock skew is detected, a flag is set, and, after the time interval has completed, clock skew S is estimated using the minimum latency values for the interval. The recorded latency values for the interval are then revised using the calculated clock skew S, and one-way latency results reported. The improved accuracy can be achieved with only on a few computations after the data have been collected. This a posteriori approach saves on computational resources, which can be at a premium for network testing equipment.

The technology includes a method, computer medium, and system for remote testing over-the-air (OTA) audio quality using a test platform positioned at core network, the test platform comprising first and second cellular handsets and bridging logic that interconnects, controls, and bridges the first and second cellular handsets. The method includes triggering the bridging logic. The bridging logic initiates a first call over the first cellular handset to a tester, and initiates a second call over the second cellular handset to a destination, wherein the second call is initiated over-the-air. The bridging logic and the first and second cellular handsets are positioned in a location that causes routing by a cellular network of the first call over a segment under test. The bridging logic bridging audio between the first and the second calls, including relaying audio. The tester determines that the second call was established based on the relayed audio.

The disclosed technology teaches creating a real time visualization and analysis of Wi-Fi performance and behavior of a DUT in wireless communication with a selected Wi-Fi test device. Also included is performing a radiated test of the DUT using transceiver signals from multiple test antennas impinging on antennas of the DUT, capturing packet details of traffic between the DUT and the selected Wi-Fi test device using a sniffer that is RF coupled to antennas of the selected Wi-Fi test device, and generating a time series summary stream in real time from the packet details captured by the sniffer, including summaries of both performance and behavior metrics. The performance metrics summarize throughput and other measured characteristics of a received signal and the behavior metrics capture transmitter settings that the DUT and test devices choose. Also included is generating scrolling visualizations of selected metrics from the stream as the radiated test proceeds.

The technology disclosed teaches a method of testing performance of a device-under-test during cloud gaming over a live cellular network. The method comprises instrumenting the device-under-test with at least one instrument app that interacts with a browser on the device-under-test and captures performance metrics from gaming network traffic. The browser and the instrument app can be invoked using a test controller separated from the device-under-test, causing the browser to connect to a gaming simulation over the live cellular network. A segmented gaming image stream is transmitted to the browser, with segmented playing at varying bit rates and image complexity while the instrument app causes the browser to transmit artificial gameplay events to a gaming simulation test server. Performance metrics from the gaming network traffic are captured, as well as gaming images rendered by the browser during the segmented gaming image stream.